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Sample records for burst alert telescope

  1. Testing and Performance of UFFO Burst Alert & Trigger Telescope

    DEFF Research Database (Denmark)

    Rípa, Jakub; Bin Kim, Min; Lee, Jik

    2014-01-01

    The Ultra-Fast Flash Observatory pathfinder (UFFO-p) is a new space mission dedicated to detect Gamma-Ray Bursts (GRBs) and rapidly follow their afterglows in order to provide early optical/ultraviolet measurements. A GRB location is determined in a few seconds by the UFFO Burst Alert & Trigger...... telescope (UBAT) employing the coded mask imaging technique and the detector combination of Yttrium Oxyorthosilicate (YSO) scintillating crystals and multi-anode photomultiplier tubes. The results of the laboratory tests of UBAT’s functionality and performance are described in this article. The detector...

  2. Exploring the Pulse Structure of the Gamma-Ray Bursts from the Swift Burst Alert Telescop

    Science.gov (United States)

    Martinez, Juan-Carlos; Team 1: Jon Hakkila, Amy Lien, Judith, Racusin, Team 2: Antonino Cucchiara, David Morris

    2018-01-01

    Gamma-ray bursts (GRBs) are one of the brightest and most intense explosions in our universe. For this project, we studied the shape of 400 single pulse GRBs using data gathered from Swift's Burst Alert Telescope (BAT). Hakkila et al. (2015) have discovered a mathematical Model that describes the GRB’s pulse shapes. Following the method in Hakkila et al. (2015), we fit GRB pulses with the Norris function and examined the residual in the fitting, to see whether the results are consistent with the one reported in Hakkila et al. (2015).

  3. Design and implementation of the UFFO burst alert and trigger telescope

    DEFF Research Database (Denmark)

    Kim, J.E.; Ahmad, S.; Barrillon, P.

    2012-01-01

    The Ultra Fast Flash Observatory pathfinder (UFFO-p) is a telescope system designed for the detection of the prompt optical/UV photons from Gamma-Ray Bursts (GRBs), and it will be launched onboard the Lomonosov spacecraft in 2012. The UFFO-p consists of two instruments: the UFFO Burst Alert...... and Trigger telescope (UBAT) for the detection and location of GRBs, and the Slewing Mirror Telescope (SMT) for measurement of the UV/optical afterglow. The UBAT isa coded-mask aperture X-ray camera with a wide field of view (FOV) of 1.8 sr. The detector module consists of the YSO(Yttrium Oxyorthosilicate...

  4. Design and Fabrication of Detector Module for UFFO Burst Alert & Trigger Telescope

    DEFF Research Database (Denmark)

    Jung, A.; Ahmad, S.; Ahn, K. -B.

    2011-01-01

    The Ultra-Fast Flash Observatory (UFFO) pathfinder is a space mission devoted to the measurement of Gamma-Ray Bursts (GRBs), especially their early light curves which will give crucial information on the progenitor stars and central engines of the GRBs. It consists of two instruments: the UFFO...... Burst Alert & Trigger telescope (UBAT) for the detection of GRB locations and the Slewing Mirror Telescope (SMT) for the UV/optical afterglow observations, upon triggering by UBAT. The UBAT employs a coded-mask {\\gamma}/X-ray camera with a wide field of view (FOV), and is comprised of three parts...

  5. DO THE FERMI GAMMA-RAY BURST MONITOR AND SWIFT BURST ALERT TELESCOPE SEE THE SAME SHORT GAMMA-RAY BURSTS?

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Eric; Briggs, Michael S. [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Connaughton, Valerie [Universities Space Research Association, Science and Technology Institute, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Zhang, Bin-Bin [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Lien, Amy [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Goldstein, Adam [NASA Postdoctoral Program, Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Pelassa, Veronique [Smithsonian Astrophysical Observatory, P.O. Box 97, Amado, AZ 85645 (United States); Troja, Eleonora, E-mail: eb0016@uah.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Compact binary system mergers are expected to generate gravitational radiation detectable by ground-based interferometers. A subset of these, the merger of a neutron star with another neutron star or a black hole, are also the most popular model for the production of short gamma-ray bursts (GRBs). The Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM) trigger on short GRBs (SGRBs) at rates that reflect their relative sky exposures, with the BAT detecting 10 per year compared to about 45 for GBM. We examine the SGRB populations detected by Swift BAT and Fermi GBM. We find that the Swift BAT triggers on weaker SGRBs than Fermi GBM, providing they occur close to the center of the BAT field of view, and that the Fermi GBM SGRB detection threshold remains flatter across its field of view. Overall, these effects combine to give the instruments the same average sensitivity, and account for the SGRBs that trigger one instrument but not the other. We do not find any evidence that the BAT and GBM are detecting significantly different populations of SGRBs. Both instruments can detect untriggered SGRBs using ground searches seeded with time and position. The detection of SGRBs below the on-board triggering sensitivities of Swift BAT and Fermi GBM increases the possibility of detecting and localizing the electromagnetic counterparts of gravitational wave (GW) events seen by the new generation of GW detectors.

  6. Superorbital Periodic Modulation in Wind-Accretion High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    Science.gov (United States)

    Corbet, Robin H. D.; Krimm, Hans A.

    2013-01-01

    We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

  7. Probing the Cosmic Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    Science.gov (United States)

    Lien, Amy; Sakamoto, Takanori; Gehrels, Neil; Palmer, David M.; Barthelmy, Scott D.; Graziani, Carlo; Cannizzo, John K.

    2013-01-01

    The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously own GRB instruments, Swift has over 500 trigger criteria based on photon count rate and additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we develop a program that is capable of simulating all the rate trigger criteria and mimicking the image threshold. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection rate of dim bursts. As a result, our simulations suggest bursts need to be dimmer than previously expected to avoid over-producing the number of detections and to match with Swift observations. Moreover, our results indicate that these dim bursts are more likely to be high redshift events than low-luminosity GRBs. This would imply an even higher cosmic GRB rate at large redshifts than previous expectations based on star-formation rate measurements, unless other factors, such as the luminosity evolution, are taken into account. The GRB rate from our best result gives a total number of 4568 +825 -1429 GRBs per year that are beamed toward us in the whole universe.

  8. The 60 Month All-Sky Burst Alert Telescope Survey of Active Galactic Nucleus and the Anisotropy of Nearby AGNs

    Science.gov (United States)

    Ajello, M.; Alexander, D. M.; Greiner, J.; Madejeski, G. M.; Gehrels, N.; Burlon, D.

    2014-01-01

    Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). We present the results of 60 months of observation of the hard X-ray sky with Swift/Burst Alert Telescope (BAT). In this time frame, BAT-detected (in the 15-55 keV band) 720 sources in an all-sky survey of which 428 are associated with AGNs, most of which are nearby. Our sample has negligible incompleteness and statistics a factor of approx. 2 larger over similarly complete sets of AGNs. Our sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent approx. 5% of AGN samples detected above 15 keV. We use the BAT data set to refine the determination of the log N-log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. We show that the log N-log S of AGNs selected above 10 keV is now established to approx. 10% precision. We derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9(+4.1/-2.9)× 10(exp -5)/cubic Mpc for objects with a de-absorbed luminosity larger than 2 × 10(exp 42) erg / s. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. We find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (much < 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions..

  9. Diverse Long-Term Variability of Five Candidate High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    Science.gov (United States)

    Corbet, Robin H. D.; Coley, Joel B.; Krimm, Hans A.

    2017-01-01

    We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope (SWIFT-BAT). IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with the Swift X-ray Telescope show a hint of pulsations at 33.4 seconds. For AX J1700.2-4220, 54 second-pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090,which was previously proposed to be a Be star system with an orbital period of approximately 30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although theymight be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be starmass donors.

  10. UBAT of UFFO/Lomonosov: The X-Ray Space Telescope to Observe Early Photons from Gamma-Ray Bursts

    DEFF Research Database (Denmark)

    Jeong, S.; Panasyuk, M. I.; Reglero, V.

    2018-01-01

    The Ultra-Fast Flash Observatory (UFFO) Burst Alert and Trigger Telescope (UBAT) has been designed and built for the localization of transient X-ray sources such as Gamma Ray Bursts (GRBs). As one of main instruments in the UFFO payload onboard the Lomonosov satellite (hereafter UFFO/Lomonosov), ...

  11. Prospects for Gamma-Ray Burst detection by the Cherenkov Telescope Array

    Directory of Open Access Journals (Sweden)

    Bissaldi E.

    2017-01-01

    Full Text Available The Large Area Telescope (LAT on the Fermi satellite is expected to publish a catalogue with more than 100 Gamma-Ray Bursts (GRBs detected above 100 MeV thanks to a new detection algorithm and a new event reconstruction. This work aims at revising the prospects for GRB alerts with the Cherenkov Telescope Array (CTA based on the new LAT results. We start considering the simulation of the observations with the full CTA of two extremely bright events, the long GRB 130427A and the short GRB 090510, then we investigate how these GRBs would be observed by a particular configuration of the array with the telescopes pointing to different directions in what is called the “coupled divergent mode”.

  12. Optical telescope BIRT in ORIGIN for gamma ray burst observing

    DEFF Research Database (Denmark)

    Content, Robert; Content, Robert; Sharples, Ray

    2012-01-01

    The ORIGIN concept is a space mission with a gamma ray, an X-ray and an optical telescope to observe the gamma ray bursts at large Z to determine the composition and density of the intergalactic matter in the line of sight. It was an answer to the ESA M3 call for proposal. The optical telescope i...... length. All 3 instruments use the same 2k x 2k detector simultaneously so that telescope pointing and tip-tilt control of a fold mirror permit to place the gamma ray burst on the desired instrument without any other mechanism. © 2012 SPIE.......The ORIGIN concept is a space mission with a gamma ray, an X-ray and an optical telescope to observe the gamma ray bursts at large Z to determine the composition and density of the intergalactic matter in the line of sight. It was an answer to the ESA M3 call for proposal. The optical telescope....... All instruments fit together in a box of 80 mm x 80 mm x 200 mm. The low resolution spectrograph uses a very compact design including a special triplet. It contains only spherical surfaces except for one tilted cylindrical surface to disperse the light. To reduce the need for a high precision pointing...

  13. Stacked search for time shifted high energy neutrinos from gamma ray bursts with the Antares neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Adrian-Martinez, S.; Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M. [Universitat Politecnica de Valencia, Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Gandia (Spain); Albert, A.; Drouhin, D.; Racca, C. [GRPHE-Institut Universitaire de Technologie de Colmar, 34 rue du Grillenbreit, BP 50568, Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Vilanova i la Geltru, Barcelona (Spain); Anghinolfi, M. [INFN-Sezione di Genova, Genoa (Italy); Anton, G.; Eberl, T.; Enzenhoefer, A.; Fehn, K.; Folger, F.; Geisselsoeder, S.; Geyer, K.; Gleixner, A.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Richter, R.; Roensch, K.; Schmid, J.; Schnabel, J.; Seitz, T.; Sieger, C.; Tselengidou, M.; Wagner, S. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Mathieu, A.; Vallee, C. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Baret, B.; Barrios-Marti, J.; Hernandez-Rey, J.J.; Sanchez-Losa, A.; Toennis, C.; Zornoza, J.D.; Zuniga, J. [CSIC-Universitat de Valencia, IFIC-Instituto de Fisica Corpuscular, Edificios Investigacion de Paterna, Paterna, Valencia (Spain); Basa, S.; Marcelin, M.; Nezri, E. [Pole de l' Etoile Site de Chateau-Gombert, LAM-Laboratoire d' Astrophysique de Marseille, Marseille Cedex 13 (France); Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A. [INFN-Laboratori Nazionali del Sud (LNS), Catania (Italy); Bormuth, R.; Jong, M. de; Samtleben, D.F.E. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit Leiden, Leids Instituut voor Onderzoek in Natuurkunde, Leiden (Netherlands); Bouwhuis, M.C.; Heijboer, A.J.; Michael, T.; Steijger, J.J.M.; Visser, E. [Nikhef, Science Park, Amsterdam (Netherlands); Bruijn, R. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Capone, A.; De Bonis, G.; Fermani, P.; Perrina, C. [INFN-Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Caramete, L.; Pavalas, G.E.; Popa, V. [Institute for Space Sciences, Bucharest, Magurele (Romania); Chiarusi, T. [INFN-Sezione di Bologna, Bologna (Italy); Circella, M. [INFN-Sezione di Bari, Bari (Italy); Creusot, A.; Galata, S.; Gracia-Ruiz, R.; Van Elewyck, V. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Dekeyser, I.; Lefevre, D.; Tamburini, C. [Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Marseille Cedex 9 (France); Universite du Sud Toulon-Var, CNRS-INSU/IRD UM 110, La Garde Cedex (France); Deschamps, A.; Hello, Y. [Geoazur, Universite Nice Sophia-Antipolis, CNRS/INSU, IRD, Observatoire de la Cote d' Azur, Sophia Antipolis (France); Donzaud, C. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Universite Paris-Sud, Orsay Cedex (France); Dumas, A.; Gay, P. [Clermont Universite, Universite Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, Clermont-Ferrand (France); Elsaesser, D.; Kadler, M.; Kreter, M.; Mueller, C. [Universitaet Wuerzburg, Institut fuer Theoretische Physik und Astrophysik, Wuerzburg (Germany); Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M. [INFN-Sezione di Bologna, Bologna (Italy); Dipartimento di Fisica dell' Universita, Bologna (Italy); Giordano, V. [INFN-Sezione di Catania, Catania (Italy); Haren, H. van [Royal Netherlands Institute for Sea Research (NIOZ), ' t Horntje, Texel (Netherlands); Hugon, C.; Taiuti, M. [INFN-Sezione di Genova, Genoa (Italy); Dipartimento di Fisica dell' Universita, Genoa (Italy); Kooijman, P. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit Utrecht, Faculteit Betawetenschappen, Utrecht (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Kouchner, A. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Institut Universitaire de France, Paris (France); Kreykenbohm, I.; Wilms, J. [Universitaet Erlangen-Nuernberg, Dr. Remeis-Sternwarte and ECAP, Bamberg (Germany); Kulikovskiy, V. [INFN-Laboratori Nazionali del Sud (LNS), Catania (Italy); Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Leonora, E. [INFN-Sezione di Catania, Catania (Italy); Dipartimento di Fisica ed Astronomia dell' Universita, Catania (Italy); Loucatos, S. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); CEA Saclay, Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service de Physique des Particules, Gif-sur-Yvette Cedex (France); Marinelli, A. [INFN-Sezione di Pisa, Pisa (Italy); Dipartimento di Fisica dell' Universita, Pisa (Italy); Migliozzi, P. [INFN-Sezione di Napoli, Naples (IT); Moussa, A. [University Mohammed I, Laboratory of Physics of Matter and Radiations, Oujda (MA); Pradier, T. [Universite de Strasbourg et CNRS/IN2P3, IPHC-Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, BP 28, Strasbourg Cedex 2 (FR); Sanguineti, M. [Dipartimento di Fisica dell' Universita, Genoa (IT); Schuessler, F.; Stolarczyk, T.; Vallage, B. [CEA Saclay, Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service de Physique des Particules, Gif-sur-Yvette Cedex (FR); Vivolo, D. [INFN-Sezione di Napoli, Naples (IT); Dipartimento di Fisica dell' Universita Federico II di Napoli, Naples (IT)

    2017-01-15

    A search for high-energy neutrino emission correlated with gamma-ray bursts outside the electromagnetic prompt-emission time window is presented. Using a stacking approach of the time delays between reported gamma-ray burst alerts and spatially coincident muon-neutrino signatures, data from the Antares neutrino telescope recorded between 2007 and 2012 are analysed. One year of public data from the IceCube detector between 2008 and 2009 have been also investigated. The respective timing profiles are scanned for statistically significant accumulations within 40 days of the Gamma Ray Burst, as expected from Lorentz Invariance Violation effects and some astrophysical models. No significant excess over the expected accidental coincidence rate could be found in either of the two data sets. The average strength of the neutrino signal is found to be fainter than one detectable neutrino signal per hundred gamma-ray bursts in the Antares data at 90% confidence level. (orig.)

  14. UBAT of UFFO/ Lomonosov: The X-Ray Space Telescope to Observe Early Photons from Gamma-Ray Bursts

    Science.gov (United States)

    Jeong, S.; Panasyuk, M. I.; Reglero, V.; Connell, P.; Kim, M. B.; Lee, J.; Rodrigo, J. M.; Ripa, J.; Eyles, C.; Lim, H.; Gaikov, G.; Jeong, H.; Leonov, V.; Chen, P.; Castro-Tirado, A. J.; Nam, J. W.; Svertilov, S.; Yashin, I.; Garipov, G.; Huang, M.-H. A.; Huang, J.-J.; Kim, J. E.; Liu, T.-C.; Petrov, V.; Bogomolov, V.; Budtz-Jørgensen, C.; Brandt, S.; Park, I. H.

    2018-02-01

    The Ultra-Fast Flash Observatory (UFFO) Burst Alert and Trigger Telescope (UBAT) has been designed and built for the localization of transient X-ray sources such as Gamma Ray Bursts (GRBs). As one of main instruments in the UFFO payload onboard the Lomonosov satellite (hereafter UFFO/ Lomonosov), the UBAT's roles are to monitor the X-ray sky, to rapidly locate and track transient sources, and to trigger the slewing of a UV/optical telescope, namely Slewing Mirror Telescope (SMT). The SMT, a pioneering application of rapid slewing mirror technology has a line of sight parallel to the UBAT, allowing us to measure the early UV/optical GRB counterpart and study the extremely early moments of GRB evolution. To detect X-rays, the UBAT utilizes a 191.1 cm2 scintillation detector composed of Yttrium Oxyorthosilicate (YSO) crystals, Multi-Anode Photomultiplier Tubes (MAPMTs), and associated electronics. To estimate a direction vector of a GRB source in its field of view, it employs the well-known coded aperture mask technique. All functions are written for implementation on a field programmable gate array to enable fast triggering and to run the device's imaging algorithms. The UFFO/ Lomonosov satellite was launched on April 28, 2016, and is now collecting GRB observation data. In this study, we describe the UBAT's design, fabrication, integration, and performance as a GRB X-ray trigger and localization telescope, both on the ground and in space.

  15. The bursts of high energy events observed by the telescope array surface detector

    Science.gov (United States)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kishigami, S.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Onogi, R.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Saito, K.; Saito, Y.; Sakaki, N.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Sekino, K.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2017-08-01

    The Telescope Array (TA) experiment is designed to detect air showers induced by ultra high energy cosmic rays. The TA ground Surface particle Detector (TASD) observed several short-time bursts of air shower like events. These bursts are not likely due to chance coincidence between single shower events. The expectation of chance coincidence is less than 10-4 for five-year's observation. We checked the correlation between these bursts of events and lightning data, and found evidence for correlations in timing and position. Some features of the burst events are similar to those of a normal cosmic ray air shower, and some are not. On this paper, we report the observed bursts of air shower like events and their correlation with lightning.

  16. Gamma-ray burst science in the era of the Cherenkov Telescope Array

    NARCIS (Netherlands)

    Inoue, S.; Granof, J.; O'Brien, P.T.; Asano, K.; Bouvier, A.; Carosi, A.; Connaughton, V.; Garczarczyk, M.; Gilmore, R.; Hinton, J.; Inoue, Y.; Kakuwa, J.; Markoff, S.; Murase, K.; Osborne, J.P.; Nepomuk Otte, A.; Starling, R.; Tajima, H.; Teshima, M.; Toma, K.; Wagner, S.; Wijers, R.A.M.J.; Williams, D.A.; Yamamoto, T.; Yamazaki, R.

    2013-01-01

    We outline the science prospects for gamma-ray bursts (GRBs) with the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory operating at energies above few tens of GeV. With its low energy threshold, large effective area and rapid slewing capabilities, CTA will be

  17. Gaia science alerts and the observing facilities of the Serbian-Bulgarian mini-network telescopes

    Directory of Open Access Journals (Sweden)

    Damljanović G.

    2014-01-01

    Full Text Available The astrometric European Space Agency (ESA Gaia mission was launched in December 19, 2013. One of the tasks of the Gaia mission is production of an astrometric catalog of over one billion stars and more than 500000 extragalactic sources. The quasars (QSOs, as extragalactic sources and radio emitters, are active galactic nuclei objects (AGNs whose coordinates are well determined via Very Long Baseline Interferometry (VLBI technique and may reach sub-milliarcsecond accuracy. The QSOs are the defining sources of the quasi-inertial International Celestial Reference Frame (ICRF because of their core radio morphology, negligible proper motions (until sub-milliarcsecond per year, and apparent point-like nature. Compact AGNs, visible in optical domain, are useful for a direct link of the future Gaia optical reference frame with the most accurate radio one. Apart from the above mentioned activities, Gaia has other goals such as follow-up of transient objects. One of the most important Gaia's requirements for photometric alerts is a fast observation and reduction response, that is, submition of observations within 24 hours. For this reason we have developed a pipeline. In line with possibilities of our new telescope (D(cm/F(cm=60/600 at the Astronomical Station Vidojevica (ASV, of the Astronomical Observatory in Belgrade, we joined the Gaia-Follow-Up Network for Transients Objects (Gaia-FUN-TO for the photometric alerts. Moreover, in view of the cooperation with Bulgarian colleagues (in the frst place, SV, one of us (GD initiated a local mini-network of Serbian { Bulgarian telescopes useful for the Gaia-FUN-TO and other astronomical purposes. During the next year we expect a new 1.4 m telescope at ASV site. The speed of data processing (from observation to calibration server could be one day. Here, we present an overview of our activities in the Gaia-FUN-TO which includes establishing Serbian { Bulgarian mini-network (of five telescopes at three sites

  18. Observation of early photons from gamma-ray bursts with the Lomonosov / UFFO-pathfinder

    DEFF Research Database (Denmark)

    Jeong, S.; Brandt, Søren; Budtz-Jørgensen, Carl

    2014-01-01

    UFFO-pathfinder is a pioneering space mission to observe the early evolution of Gamma-ray Bursts using a fast slewing strategy. It consists of the Slewing Mirror Telescope, for rapid pointing at UV/optical wavelengths and the UFFO Burst Alert and Trigger Telescope. It has a total weight of ~ 20 k...

  19. Imaging and burst location with the EXIST high-energy telescope

    Science.gov (United States)

    Skinner, Gerald K.; Barthelmy, Scott; Finger, Mark H.; Hong, Jae Sub; Jernigan, Garrett; Sturner, Steven J.; Allen, Branden T.; Grindlay, Jonathan E.

    2009-08-01

    The primary instrument of the proposed EXIST mission is a coded mask high energy telescope (the HET), that must have a wide field of view and extremely good sensitivity. In order to achieve the performance goals it will be crucial to minimize systematic errors so that even for very long total integration times the imaging performance is close to the statistical photon limit. There is also a requirement to be able to reconstruct images on-board in near real time in order to detect and localize gamma-ray bursts, as is currently being done by the BAT instrument on Swift. However for EXIST this must be done while the spacecraft is continuously scanning the sky. The scanning provides all-sky coverage and is also a key part of the strategy to reduce systematic errors. The on-board computational problem is made even more challenging for EXIST by the very large number of detector pixels (more than 107, compared with 32768 for BAT). The EXIST HET Imaging Technical Working Group has investigated and compared numerous alternative designs for the HET. The selected baseline concept meets all of the scientific requirements, while being compatible with spacecraft and launch constraints and with those imposed by the infra-red and soft X-ray telescopes that constitute the other key parts of the payload. The approach adopted depends on a unique coded mask with two spatial scales. Coarse elements in the mask are effective over the entire energy band of the instrument and are used to initially locate gamma-ray bursts. A finer mask component provides the good angular resolution needed to refine the burst position and reduces the cosmic X-ray background; it is optimized for operation at low energies and becomes transparent in the upper part of the energy band where an open fraction of 50% is optimal. Monte Carlo simulations and analytic analysis techniques have been used to demonstrate the capabilities of the proposed design and of the two-step burst localization procedure.

  20. Slewing Mirror Telescope optics for the early observation of UV/optical photons from Gamma-Ray Bursts

    DEFF Research Database (Denmark)

    Jeong, S.; Nam, J. W.; Ahn, K. B.

    2013-01-01

    We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of ...

  1. EXIST's Gamma-Ray Burst Sensitivity

    Science.gov (United States)

    Band, D. L.; Grindlay, J. E.; Hong, J.; Fishman, G.; Hartmann, D. H.; Garson, A., III; Krawczynski, H.; Barthelmy, S.; Gehrels, N.; Skinner, G.

    2008-02-01

    We use semianalytic techniques to evaluate the burst sensitivity of designs for the EXIST hard X-ray survey mission. Applying these techniques to the mission design proposed for the Beyond Einstein program, we find that with its very large field of view and faint gamma-ray burst detection threshold, EXIST will detect and localize approximately two bursts per day, a large fraction of which may be at high redshift. We estimate that EXIST's maximum sensitivity will be ~4 times greater than that of Swift's Burst Alert Telescope. Bursts will be localized to better than 40'' at threshold, with a burst position as good as a few arcseconds for strong bursts. EXIST's combination of three different detector systems will provide spectra from 3 keV to more than 10 MeV. Thus, EXIST will enable a major leap in the understanding of bursts, their evolution, environment, and utility as cosmological probes.

  2. Constraints on Lorentz Invariance Violation from Fermi -Large Area Telescope Observations of Gamma-Ray Bursts

    Science.gov (United States)

    Vasileiou, V.; Jacholkowska, A.; Piron, F.; Bolmont, J.; Courturier, C.; Granot, J.; Stecker, Floyd William; Cohen-Tanugi, J.; Longo, F.

    2013-01-01

    We analyze the MeV/GeV emission from four bright Gamma-Ray Bursts (GRBs) observed by the Fermi-Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some Quantum Gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the "QG energy scale" (the energy scale that LIV-inducing QG effects become important, E(sub QG)) and the coefficients of the Standard Model Extension. For the subluminal case (where high energy photons propagate more slowly than lower energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% CL) are obtained from GRB 090510 and are E(sub QG,1) > 7.6 times the Planck energy (E(sub Pl)) and E(sub QG,2) > 1.3×10(exp 11) GeV for linear and quadratic leading order LIV-induced vacuum dispersion, respectively. These limits improve the latest constraints by Fermi and H.E.S.S. by a factor of approx. 2. Our results disfavor any class of models requiring E(sub QG,1) < or approx. E(sub Pl)

  3. Slewing Mirror Telescope optics for the early observation of UV/optical photons from Gamma-Ray Bursts.

    Science.gov (United States)

    Jeong, S; Nam, J W; Ahn, K B; Park, I H; Kim, S W; Lee, J; Lim, H; Brandt, S; Budtz-Jørgensen, C; Castro-Tirado, A J; Chen, P; Cho, M H; Choi, J N; Grossan, B; Huang, M A; Jung, A; Kim, J E; Kim, M B; Kim, Y W; Linder, E V; Min, K W; Na, G W; Panasyuk, M I; Ripa, J; Reglero, V; Smoot, G F; Suh, J E; Svertilov, S; Vedenkin, N; Yashin, I

    2013-01-28

    We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT can deliver the images of GRB optical counterparts to the intensified CCD detector within 1.5~1.8 s over ± 35 degrees in the slewing field of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides a 17 × 17 arcmin² instantaneous field of view. Technical details of design, construction, the laboratory performance tests in space environments for this unique SMT are described in conjunction with the plan for in-orbit operation onboard the Lomonosov satellite in 2013.

  4. Automated rapid follow-up of Swift gamma-ray burst alerts at 15 GHz with the AMI Large Array

    NARCIS (Netherlands)

    Staley, T.D.; Titterington, D.J.; Fender, R.P.; Swinbank, J.D.; van der Horst, A.J.; Rowlinson, A.; Scaife, A.M.M.; Grainge, K.J.B.; Pooley, G.G.

    2013-01-01

    We present 15-GHz follow-up radio observations of 11 Swift gamma-ray burst (GRB) sources, obtained with the Arcminute Microkelvin Imager Large Array (AMI-LA). The initial follow-up observation for each source was made in a fully automated fashion; as a result four observations were initiated within

  5. The host galaxies and explosion sites of long-duration gamma ray bursts: Hubble Space Telescope near-infrared imaging

    Science.gov (United States)

    Lyman, J. D.; Levan, A. J.; Tanvir, N. R.; Fynbo, J. P. U.; McGuire, J. T. W.; Perley, D. A.; Angus, C. R.; Bloom, J. S.; Conselice, C. J.; Fruchter, A. S.; Hjorth, J.; Jakobsson, P.; Starling, R. L. C.

    2017-05-01

    We present the results of a Hubble Space Telescope WFC3/F160W Snapshot survey of the host galaxies of 39 long-duration gamma-ray bursts (LGRBs) at z evidence for evolution of the population of LGRB hosts towards lower luminosity, higher concentrated hosts at lower redshifts. Their half-light radii are consistent with other LGRB host samples where measurements were made on rest-frame UV observations. In agreement with recent work, we find their 80 per cent enclosed flux radii distribution to be more extended than previously thought, making them intermediate between core-collapse supernova (CCSN) and superluminous supernova (SLSN) hosts. The galactocentric projected-offset distribution confirms LGRBs as centrally concentrated, much more so than CCSNe and similar to SLSNe. LGRBs are strongly biased towards the brighter regions in their host light distributions, regardless of their offset. We find a correlation between the luminosity of the LGRB explosion site and the intrinsic column density, NH, towards the burst.

  6. Readout of the UFFO Slewing Mirror Telescope to detect UV/optical photons from Gamma-Ray Bursts

    DEFF Research Database (Denmark)

    Kim, J. E.; Lim, H.; Nam, J. W.

    2013-01-01

    The Slewing Mirror Telescope (SMT) was proposed for rapid response to prompt UV/optical photons from Gamma-Ray Bursts (GRBs). The SMT is a key component of the Ultra-Fast Flash Observatory (UFFO)-pathfinder, which will be launched aboard the Lomonosov spacecraft at the end of 2013. The SMT utilizes...... a motorized mirror that slews rapidly forward to its target within a second after triggering by an X-ray coded mask camera, which makes unnecessary a reorientation of the entire spacecraft. Subsequent measurement of the UV/optical is accomplished by a 10 cm aperture Ritchey-Chrètien telescope and the focal...... plane detector of Intensified Charge-Coupled Device (ICCD). The ICCD is sensitive to UV/optical photons of 200–650 nm in wavelength by using a UV-enhanced S20 photocathode and amplifies photoelectrons at a gain of 104–106 in double Micro-Channel Plates. These photons are read out by a Kodak KAI-0340...

  7. The Uffo Slewing Mirror Telescope for Early Optical Observation from Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Nam, Jiwoo; Ahmad, S.; Ahn, K.

    2013-01-01

    While some space born observatories, such as SWIFT and FERMI, have been operating, early observation of optical after grow of GRBs is still remained as an unexplored region. The Ultra-Fast Flash Observatory (UFFO) project is a space observatory for optical follow-ups of GRBs, aiming to explore...... the first 60 seconds of GRBs optical emission. Using fast moving mirrors to redirect our optical path rather than slewing the entire spacecraft, UFFO is utilized to catch early optical emissions from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope which is going to be on board...... of the Lomonosov satellite and launched in middle of 2012. We will discuss about scientific potentials of the UFFO project and present the payload development status, especially for Slewing Mirror Telescope which is the key instrument of the UFFO-pathfinder mission....

  8. The UFFO slewing mirror telescope for early optical observation from gamma ray bursts

    DEFF Research Database (Denmark)

    NAM, JIWOO; AHMAD, S.; AHN, K.

    2013-01-01

    While some space born observatories, such as SWIFT and FERMI, have been operating, early observation of optical after grow of GRBs is still remained as an unexplored region. The Ultra-Fast Flash Observatory (UFFO) project is a space observatory for optical follow-ups of GRBs, aiming to explore...... the first 60 seconds of GRBs optical emission. Using fast moving mirrors to redirect our optical path rather than slewing the entire spacecraft, UFFO is utilized to catch early optical emissions from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope which is going to be on board...... of the Lomonosov satellite and launched in middle of 2012. We will discuss about scientific potentials of the UFFO project and present the payload development status, especially for Slewing Mirror Telescope which is the key instrument of the UFFO-pathfinder mission....

  9. Search for muon neutrinos from Gamma-Ray Bursts with the IceCube neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Abbasi, R

    2010-01-19

    We present the results of searches for high-energy muon neutrinos from 41 gamma- ray bursts (GRBs) in the northern sky with the IceCube detector in its 22-string con-figuration active in 2007/2008. The searches cover both the prompt and a possible precursor emission as well as a model-independent, wide time window of -1 h to +3 haround each GRB. In contrast to previous searches with a large GRB population, we do not utilize a standard Waxman?Bahcall GRB flux for the prompt emission but calcu- late individual neutrino spectra for all 41 GRBs from the burst parameters measured by satellites. For all three time windows the best estimate for the number of signal events is zero. Therefore, we place 90percent CL upper limits on the fluence from the prompt phase of 3.7 x 10-3 erg cm-2 (72TeV - 6.5 PeV) and on the fluence from the precursor phase of 2.3 x 10-3 erg cm-2 (2.2TeV - 55TeV), where the quoted energy ranges contain 90percent of the expected signal events in the detector. The 90percent CL upper limit for the wide time window is 2.7 x 10-3 erg cm-2 (3TeV - 2.8 PeV) assuming an E-2 flux.

  10. The slewing mirror telescope of the Ultra Fast Flash Observatory Pathfinder

    DEFF Research Database (Denmark)

    Jeong, S.; Ahmad, S.; Barrillon, P.

    2012-01-01

    the Russian Lomonosov satellite in November 2012 by Soyuz-2 rocket. Once the UFFO Burst Alert & Trigger Telescope (UBAT) detects the GRBs, Slewing mirror (SM) will slew to bring new GRB into the SMT’s field of view rather than slewing the entire spacecraft. SMT can give a UV/Optical counterpart position...

  11. Do Fermi Large Area Telescope observations imply very large Lorentz factors in gamma-ray burst outflows?

    Science.gov (United States)

    Hascoët, R.; Daigne, F.; Mochkovitch, R.; Vennin, V.

    2012-03-01

    Recent detections of GeV photons in a few gamma-ray bursts (GRBs) by Fermi Large Area Telescope (LAT) imply huge bulk Lorentz factors to avoid a large γγ optical depth at high energy. Estimates can be as high as Γ≃ 103 in the most extreme cases. This puts severe constraints on models of the central engine and the jet acceleration in GRBs. These estimates are, however, obtained from a simplified single-zone model. We present here a more realistic calculation of the γγ opacity which takes into account the time, space and direction dependent photon field existing in an outflow with several relativistically moving emitting zones. The formalism is very general and can be applied to many models of the prompt GRB emission. We present results obtained for a numerical implementation in the framework of the internal shock model. We show the following results in this paper. (i) The minimum Lorentz factor Γmin in bright Fermi-LAT GRBs is reduced by a factor of ≃2-3 compared to previous estimates if the GeV and MeV emission are produced in the same region, and by an additional factor of ≃2-8 if the GeV emission is produced at larger radii. We provide an improved approximate formula for Γmin which is in good agreement with our numerical results and which can be directly applied to Fermi-LAT GRB data. (ii) A delayed onset of the GeV emission can be due to the time evolution of the opacity in a GRB outflow. As an illustration of these first two results, we present a synthetic GRB that reproduces most features of GRB 080916C with a mean Lorentz factor of ≃340, an optically thin regime for γγ opacity at 3 GeV in time bin 'b', a variability time-scale of ≃0.5 s in the MeV light curve and a delayed onset of ≃5 s of the GeV emission. (iii) The γγ opacity can smooth the short time-scale variability in the GeV light curve. This last result implies that the observed variability at high energy is not necessarily a good test to distinguish between an internal and an

  12. UNUSUAL CENTRAL ENGINE ACTIVITY IN THE DOUBLE BURST GRB 110709B

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Binbin; Burrows, David N.; Meszaros, Peter; Falcone, Abraham D. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Zhang Bing [Department of Physics, University of Nevada, Las Vegas, NV 89154 (United States); Wang Xiangyu [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Stratta, Giulia; D' Elia, Valerio [ASI-Science Data Center, Via Galileo Galilei, I-00044 Frascati (Italy); Frederiks, Dmitry; Golenetskii, Sergey [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St Petersburg 194021 (Russian Federation); Cummings, Jay R.; Barthelmy, Scott D.; Gehrels, Neil [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Norris, Jay P., E-mail: bbzhang@psu.edu [Physics Department, Boise State University, 1910 University Drive, Boise, ID 83725 (United States)

    2012-04-01

    The double burst, GRB 110709B, triggered the Swift/Burst Alert Telescope (BAT) twice at 21:32:39 UT and 21:43:45 UT, respectively, on 2011 July 9. This is the first time we observed a gamma-ray burst (GRB) with two BAT triggers. In this paper, we present simultaneous Swift and Konus-WIND observations of this unusual GRB and its afterglow. If the two events originated from the same physical progenitor, their different time-dependent spectral evolution suggests they must belong to different episodes of the central engine, which may be a magnetar-to-BH accretion system.

  13. Alcohol Alert

    Science.gov (United States)

    ... Disorders Publications & Multimedia Brochures & Fact Sheets NIAAA Journal Alcohol Alert Bulletin Professional Education Materials Classroom Resources Presentations & Videocasts Video Bank Publicaciones ...

  14. Mid-Infrared Properties of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. 1. Emission-Line Diagnostics

    Science.gov (United States)

    2010-06-20

    sample of different sources, including our BAT AGNs, LINERs, starburst galaxies , H ii galaxies , and blue compact dwarf from high-resolution Spitzer...populations; however, six newly discovered BAT AGNs are under-luminous in [O iv], most likely the result of dust extinction in the host galaxy . The...forming galaxies , and LINERs. We find that the BAT AGN sample falls into a distinc- tive region when comparing the [Ne iii]/[Ne ii] and the [O iv]/[Ne

  15. Goddard Robotic Telescope (GRT)

    Data.gov (United States)

    National Aeronautics and Space Administration — Since it is not possible to predict when a Gamma-Ray Burst (GRB) occurs, the follow-up ground telescopes must be distributed as uniform as possible all over the...

  16. Light Dawns on Dark Gamma-ray Bursts

    Science.gov (United States)

    2010-12-01

    data with new observations made using GROND [2] - a dedicated gamma-ray burst follow-up observation instrument, which is attached to the 2.2-metre MPG/ESO telescope at La Silla in Chile. In doing so, astronomers have conclusively solved the puzzle of the missing optical afterglow. What makes GROND exciting for the study of afterglows is its very fast response time - it can observe a burst within minutes of an alert coming from Swift using a special system called the Rapid Response Mode - and its ability to observe simultaneously through seven filters covering both the visible and near-infrared parts of the spectrum. By combining GROND data taken through these seven filters with Swift observations, astronomers were able to accurately determine the amount of light emitted by the afterglow at widely differing wavelengths, all the way from high energy X-rays to the near-infrared. The astronomers used this information to directly measure the amount of obscuring dust that the light passed through en route to Earth. Previously, astronomers had to rely on rough estimates of the dust content [3]. The team used a range of data, including their own measurements from GROND, in addition to observations made by other large telescopes including the ESO Very Large Telescope, to estimate the distances to nearly all of the bursts in their sample. While they found that a significant proportion of bursts are dimmed to about 60-80 percent of the original intensity by obscuring dust, this effect is exaggerated for the very distant bursts, letting the observer see only 30-50 percent of the light [4]. The astronomers conclude that most dark gamma-ray bursts are therefore simply those that have had their small amount of visible light completely stripped away before it reaches us. "Compared to many instruments on large telescopes, GROND is a low cost and relatively simple instrument, yet it has been able to conclusively resolve the mystery surrounding dark gamma-ray bursts," says Greiner. Notes

  17. Optical and X-Ray Early Follow-Up of ANTARES Neutrino Alerts

    Science.gov (United States)

    Adrian-Martinez, S.; Ageron, M.; Albert, A.; Samarai, I. Al; Andre, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Baret, B.; Barrios-Marti, J.; hide

    2016-01-01

    High-energy neutrinos could be produced in the interaction of charged cosmic rays with matter or radiation surrounding astrophysical sources. Even with the recent detection of extraterrestrial high-energy neutrinos by the IceCube experiment, no astrophysical neutrinosource has yet been discovered. Transient sources, such as gamma-ray bursts, core-collapse supernovae, or active galactic nuclei are promising candidates. Multi-messenger programs offer a unique opportunity to detect these transient sources. By combining the information provided by the ANTARES neutrino telescope with information coming from other observatories, the probability of detecting a source is enhanced, allowing the possibility of identifyinga neutrino progenitor from a single detected event. A method based on optical and X-ray follow-ups of high-energy neutrino alerts has been developed within the ANTARES collaboration. This method does not require any assumptions on the relation between neutrino and photon spectra other than time-correlation. This program, denoted as TAToO, triggers a network of robotic optical telescopes (TAROTand ROTSE) and the Swift-XRT with a delay of only a few seconds after a neutrino detection, and is therefore well-suited to search for fast transient sources. To identify an optical or Xraycounterpart to a neutrino signal, the images provided by the follow-up observations areanalysed with dedicated pipelines. A total of 42 alerts with optical and 7 alerts with X-ray images taken with a maximum delay of 24 hours after the neutrino trigger have been analyzed. No optical or X-ray counterparts associated to the neutrino triggers have been found, and upper limits on transient source magnitudes have been derived. The probability to reject the gamma-ray burst origin hypothesis has been computed for each alert.

  18. Optical and X-ray early follow-up of ANTARES neutrino alerts

    Science.gov (United States)

    Adrián-Martínez, S.; Ageron, M.; Albert, A.; Samarai, I. Al; André, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bogazzi, C.; Bormuth, R.; Bou-Cabo, M.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Dekeyser, I.; Deschamps, A.; De Bonis, G.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Dumas, A.; Eberl, T.; Elsässer, D.; Enzenhöfer, A.; Fehn, K.; Felis, I.; Fermani, P.; Folger, F.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Gracia-Ruiz, R.; Graf, K.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Herrero, A.; Hößl, J.; Hofestädt, J.; Hugon, C.; James, C. W.; de Jong, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kooijman, P.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lambard, G.; Lattuada, D.; Lefèvre, D.; Leonora, E.; Loucatos, S.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martínez-Mora, J. A.; Martini, S.; Mathieu, A.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Neff, M.; Nezri, E.; Păvălaš, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Racca, C.; Riccobene, G.; Richter, R.; Roensch, K.; Rostovtsev, A.; Saldaña, M.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schmid, J.; Schnabel, J.; Schulte, S.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Sánchez-Losa, A.; Taiuti, M.; Tamburini, C.; Trovato, A.; Tselengidou, M.; Tönnis, C.; Turpin, D.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vecchi, M.; Visser, E.; Vivolo, D.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.; Klotz, A.; Boer, M.; Le Van Suu, A.; Akerlof, C.; Zheng, W.; Evans, P.; Gehrels, N.; Kennea, J.; Osborne, J. P.; Coward, D. M.

    2016-02-01

    High-energy neutrinos could be produced in the interaction of charged cosmic rays with matter or radiation surrounding astrophysical sources. Even with the recent detection of extraterrestrial high-energy neutrinos by the IceCube experiment, no astrophysical neutrino source has yet been discovered. Transient sources, such as gamma-ray bursts, core-collapse supernovae, or active galactic nuclei are promising candidates. Multi-messenger programs offer a unique opportunity to detect these transient sources. By combining the information provided by the ANTARES neutrino telescope with information coming from other observatories, the probability of detecting a source is enhanced, allowing the possibility of identifying a neutrino progenitor from a single detected event. A method based on optical and X-ray follow-ups of high-energy neutrino alerts has been developed within the ANTARES collaboration. This method does not require any assumptions on the relation between neutrino and photon spectra other than time-correlation. This program, denoted as TAToO, triggers a network of robotic optical telescopes (TAROT and ROTSE) and the Swift-XRT with a delay of only a few seconds after a neutrino detection, and is therefore well-suited to search for fast transient sources. To identify an optical or X-ray counterpart to a neutrino signal, the images provided by the follow-up observations are analysed with dedicated pipelines. A total of 42 alerts with optical and 7 alerts with X-ray images taken with a maximum delay of 24 hours after the neutrino trigger have been analysed. No optical or X-ray counterparts associated to the neutrino triggers have been found, and upper limits on transient source magnitudes have been derived. The probability to reject the gamma-ray burst origin hypothesis has been computed for each alert.

  19. Multi-wavelength follow-up of ANTARES neutrino alerts

    Science.gov (United States)

    Mathieu, Aurore

    2015-10-01

    Transient sources are often associated with the most violent phenomena in the Universe, where the acceleration of hadrons may occur. Such sources include gamma-ray bursts (GRBs), active galactic nuclei (AGN) or core-collapse supernovae (CCSNe), and are promising candidates for the production of high energy cosmic rays and neutrinos. The ANTARES telescope, located in the Mediterranean sea, aims at detecting these high energy neutrinos, which could reveal the presence of a cosmic ray accelerator. However, to enhance the sensitivity to transient sources, a method based on multi-wavelength follow-up of neutrino alerts has been developed within the ANTARES collaboration. This program, denoted as TAToO, triggers a network of robotic optical telescopes and the Swift-XRT with a delay of only a few seconds after a neutrino detection. The telescopes start an observation program of the corresponding region of the sky in order to detect a possible electromagnetic counterpart to the neutrino event. The work presented in this thesis covers the development and implementation of an optical image analysis pipeline, as well as the analysis of optical and X-ray data to search for fast transient sources, such as GRB afterglows, and slowly varying transient sources, such as CCSNe.

  20. Decameter Type III-Like Bursts

    Science.gov (United States)

    Melnik, V. N.; Konovalenko, A. A.; Rutkevych, B. P.; Rucker, H. O.; Dorovskyy, V. V.; Abranin, E. P.; Lecacheux, A.; Brazhenko, A. I.; Stanislavskyy, A. A.

    2007-12-01

    Starting from 1960s Type III-like bursts (Type III bursts with high drift rates) in a wide frequency range from 300 to 950MHz have been observed. These new bursts observed at certain frequency being compared to the usual Type III bursts at the same frequency show similar behaviour but feature frequency drift 2-6 times higher than the normal bursts. In this paper we report the first observations of Type III-like bursts in decameter range, carried out during summer campaigns 2002 - 2004 at UTR-2 radio telescope. The circular polarization of the bursts was measured by the radio telescope URAN-2 in 2004. The observed bursts are analyzed and compared with usual Type III bursts in the decameter range. From the analysis of over 1100 Type III-like bursts, their main parameters have been found. Characteristic feature of the observed bursts is similar to Type III-like bursts at other frequencies, i.e. measured drift rates (5-10 MHz/s) of this bursts are few times larger than that for usual Type III bursts, and their durations (1-2 s) are few times smaller than that for usual Type III bursts in this frequency band.

  1. Starlight beneath the waves : in search of TeV photon emission from Gamma-Ray Bursts with the ANTARES Neutrino Telescope

    NARCIS (Netherlands)

    Astraatmadja, Tri Laksmana

    2013-01-01

    At any given time, cosmic rays constantly shower the Earth from all direction. The origin of cosmic rays is still a mystery as their paths are deflected by magnetic fields to random directions. The most likely sources of cosmic rays are Gamma-Ray Bursts (GRB). As the most energetic events known in

  2. A Burst to See

    Science.gov (United States)

    2008-04-01

    On 19 March, Nature was particularly generous and provided astronomers with the wealth of four gamma-ray bursts on the same day. But that was not all: one of them is the most luminous object ever observed in the Universe. Despite being located in a distant galaxy, billions of light years away, it was so bright that it could have been seen, for a brief while, with the unaided eye. ESO PR Photo 08a/08 ESO PR Photo 08a/08 The REM Telescope and TORTORA Camera Gamma-ray bursts (GRBs) are short flashes of energetic gamma-rays lasting from less than a second to several minutes. They release a tremendous quantity of energy in this short time making them the most powerful events since the Big Bang. It is now widely accepted that the majority of the gamma-ray bursts signal the explosion of very massive, highly evolved stars that collapse into black holes. Gamma-ray bursts, which are invisible to our eyes, are discovered by telescopes in space. After releasing their intense burst of high-energy radiation, they become detectable for a short while in the optical and in the near-infrared. This 'afterglow' fades very rapidly, making detailed analysis possible for only a few hours after the gamma-ray detection. This analysis is important in particular in order to determine the GRB's distance and, hence, intrinsic brightness. The gamma-ray burst GRB 080319B was detected by the NASA/STFC/ASI Swift satellite. "It was so bright that it almost blinded the Swift instruments for a while," says Guido Chincarini, Italian principal investigator of the mission. A bright optical counterpart was soon identified in the Boötes Constellation (the "Bear Driver" or "Herdsman"). A host of ground-based telescopes reacted promptly to study this new object in the sky. In particular, the optical emission was detected by a few wide-field cameras on telescopes that constantly monitor a large fraction of the sky, including the TORTORA camera in symbiosis with the 0.6-m REM telescope located at La Silla

  3. A repeating fast radio burst

    Science.gov (United States)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  4. Possibility of observing high energy neutrinos from gamma bursts, with the Antanares telescope, feasibility study; Possibilite d'observation, par le telescope antares, de neutrinos de haute energie associes aux sursauts gamma et validation des techniques de detection a l'aide d'un prototype

    Energy Technology Data Exchange (ETDEWEB)

    Kouchner, A

    2001-04-01

    The European Antares collaboration intends to build a deep-sea neutrino telescope with a detection surface of about 1/10 km{sup 2} in the Mediterranean sea. The universe is transparent to neutrinos, so their study provides a unique means of improving our knowledge of the nature and origin of cosmic rays and their emission from the most powerful astrophysical sources in the cosmos. Neutrinos also offer the possibility of opening a new energy window (E>TeV) for observation of the universe. The first part of the thesis is dedicated to a study of the possibility of using the future telescope to look for correlations between gamma-ray bursts and high-energy neutrinos. It is based, on one hand, on the predictions of neutrino fluxes from gamma-ray bursts in the framework of the theoretical model of 'fireballs', and, on the other hand, on the temporal properties of the gamma-ray bursts in the 4. BATSE catalogue. The second part of the thesis presents the results obtained with a prototype detector line deployed, at the end of 1999, some forty km south-west off Marseilles. The objective was to operate a complete apparatus, similar to the future detector lines, from the shore, and under realistic conditions. Data from 7 photomultiplier tubes disposed along the detector line were transmitted through 37 km of optical fiber to the shore, where they were used to reconstruct tracks due to atmospheric muons, thus validating the detection principles and methods. (author)

  5. The rapid decline of the prompt emission in Gamma-Ray Bursts

    CERN Document Server

    Dado, Shlomo; De Rújula, Alvaro

    2008-01-01

    Many gamma ray bursts (GRBs) have been observed with the Burst-Alert and X-Ray telescopes of the SWIFT satellite. The successive `pulses' of these GRBs end with a fast decline and a fast spectral softening, until they are overtaken by another pulse, or the last pulse's decline is overtaken by a less rapidly-varying `afterglow'. The fast decline-phase has been attributed, in the standard fireball model of GRBs, to `high-latitude' synchrotron emission from a collision of two conical shells. This interpretation does not agree with the observed spectral softening. The temporal behaviour and the spectral evolution during the fast-decline phase agree with the predictions of the cannonball model of GRBs.

  6. Ultra-fast flash observatory for detecting the early photons from gamma-ray bursts

    DEFF Research Database (Denmark)

    Lim, H.; Jeong, S.; Ahn, K.-B.

    ) for the fast measurement of the UV-optical photons from GRBs, and a gamma-ray monitor for energy measurement. The triggering is done by the UFFO burst Alert & Trigger telescope (UBAT) using the hard X-ray from GRBs and the UV/optical Trigger Assistant Telescope (UTAT) using the UV/optical photons from GRBs...... a coded-mask aperture for position detection and their X-ray photons are readout by LYSO crystals and Multi-Anode photomultiplier tubes (MAPMTs) with the effective active area size of 191.1 cm2. With this design, we expect UBAT to trigger ∼44 GRBs/yr and expect SMT to detect ∼10 GRBs/yr. © 2011 IEEE....

  7. The Double Firing Burst

    Science.gov (United States)

    2008-09-01

    Astronomers from around the world combined data from ground- and space-based telescopes to paint a detailed portrait of the brightest explosion ever seen. The observations reveal that the jets of the gamma-ray burst called GRB 080319B were aimed almost directly at the Earth. Uncovering the disc ESO PR Photo 28/08 A Gamma-Ray Burst with Two Jets Read more on this illuminating blast in the additional story. GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye (ESO 08/08). In a paper to appear in the 11 September issue of Nature, Judith Racusin of Penn State University, Pennsylvania (USA), and a team of 92 co-authors report observations across the electromagnetic spectrum that began 30 minutes before the explosion and followed it for months afterwards. "We conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000," says Guido Chincarini, a member of the team. Gamma-ray bursts are the Universe's most luminous explosions. Most occur when massive stars run out of fuel. As a star collapses, it creates a black hole or neutron star that, through processes not fully understood, drives powerful gas jets outward. As the jets shoot into space, they strike gas previously shed by the star and heat it, thereby generating bright afterglows. The team believes the jet directed toward Earth contained an ultra-fast component just 0.4 degrees across (this is slightly smaller than the apparent size of the Full Moon). This jet is contained within another slightly less energetic jet about 20 times wider. The broad component is more typical of other bursts. "Perhaps every gamma-ray burst has a narrow jet, but astronomers miss it most of the time," says team member Stefano Covino. "We happened to view this monster down the barrel of the very narrow and energetic jet, and the chance for

  8. The Swift Gamma-ray Burst Explorer Mission at Penn State

    Science.gov (United States)

    Nousek, J.; Burrows, D.; Chester, M.; Roming, P.; Gehrels, N.; Swift Team

    2000-12-01

    The Swift GRB Explorer mission is designed to discover ~ 1000 new gamma-ray bursts in its three year planned life, and immediately (within tens of seconds) to start simultaneous X-ray, optical and ultraviolet observations of the GRB afterglow. After its planned launch in September, 2003, it will collect an impressive database of gamma ray bursts (reaching more sensitive limits than BATSE); uniform X-ray/UV/optical monitoring of afterglows (with a dedicated weatherless observatory with broad multi-wavelength imaging capability); and rapid followup by other observatories (utilizing a continuous ground link with burst alerts and data posted immediately to the GCN). The Penn State Swift responsibilities include development of the X-ray Telescope (with CCDs from the University of Leicester and X-ray mirrors from OAB); the UV/Optical Telescope (with instrument fabrication at MSSL and SwRI); and development of the Mission Operations Center at PSU (with support from Omitron Corp.). After launch Swift will be operated from Penn State, with data analysis pipelines and data archives at Goddard Space Flight Center, Leicester and the Italian Science Data Center. The mission, lead by Neil Gehrels of GSFC, has successfully concluded the Preliminary Design Review process, including the spacecraft to be built by SpectrumAstro. We show the current status of the PSU lead portions of the mission. Funding for the Swift project at PSU is provided by NASA Contract NAS5-00136.

  9. Point spread function and centroiding accuracy measurements with the JET-X mirror and MOS CCD detector of the Swift gamma ray burst explorer's X-ray telescope

    CERN Document Server

    Ambrosi, R M; Hutchinson, I B; Willingale, R; Wells, A; Short, A D T; Campana, S; Citterio, O; Tagliaferri, G; Burkert, W; Bräuninger, H

    2002-01-01

    The optical components of the Swift X-ray telescope (XRT) are already developed items. They are the flight spare X-ray mirror from the JET-X/Spectrum-X program and an MOS CCD (CCD22) of the type currently operating in orbit as part of the EPIC focal plane camera on XMM-Newton (SPIE 4140 (2000) 64). The JET-X mirrors were first calibrated at the Max Planck Institute for Extraterrestrial Physics' (MPE) Panter facility, Garching, Germany in 1996 (SPIE 2805 (1996) 56; SPIE 3114 (1997) 392). Half-energy widths of 16 arcsec at 1.5 keV were confirmed for the two flight mirrors and the flight spare. The calibration of the flight spare was repeated at Panter in July 2000 in order to establish whether any changes had occurred during the 4 yr that the mirror had been in storage at the OAB, Milan, Italy. The results reported in this paper confirm that the resolution of the JET-X mirrors has remained stable over this storage period. In an extension of this test program, the flight spare EPIC camera was installed at the fo...

  10. Searching the Gamma-Ray Sky for Counterparts to Gravitational Wave Sources Fermi Gamma-Ray Burst Monitor and Large Area Telescope Observations of LVT151012 and GW151226

    Science.gov (United States)

    Racusin, J. L.; Burns, E.; Goldstein, A.; Connaughton, V.; Wilson-Hodge, C. A.; Jenke, P.; Blackburn, L.; Briggs, M. S.; Broida, J.; Camp, J.; hide

    2017-01-01

    We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper bounds across large areas of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.

  11. Visual control of burst priming in the anesthetized lateral geniculate nucleus.

    Science.gov (United States)

    Denning, Kate S; Reinagel, Pamela

    2005-04-06

    Thalamic relay cells fire bursts of action potentials. Once a long hyperpolarization "primes" (deinactivates) the T-type calcium channel, a depolarizing input will "trigger" a calcium spike with a burst of action potentials. During sleep, bursts are frequent, rhythmic, and nonvisual. Bursts have been observed in alert animals, and burst timing is known to carry visual information under light anesthesia. We extend this finding by showing that bursts without visual triggers are rare. Nevertheless, if the channel were primed at random with respect to the stimulus, then bursts would have the same visual significance as single spikes. We find, however, that visual signals influence when the channel is primed. First, natural time-varying stimuli evoke more bursts than white noise. Second, specific visual stimuli reproducibly elicit bursts, whereas others reliably elicit single spikes. Therefore, visual information is encoded by the selective tagging of some responses as bursts. The visual information attributable to visual priming (as distinct from the information attributable to visual triggering of the bursts) was two bits per burst on average. Although bursts are reportedly rare in alert animals, this must be investigated as a function of visual stimulus. Moreover, we propose methods to measure the extent of both visual triggering and visual priming of bursts. Whether or not bursts are rare, our methods could help determine whether bursts in alert animals carry a distinct visual signal.

  12. Multirhythmic bursting

    Science.gov (United States)

    Butera, Robert J.

    1998-03-01

    A complex modeled bursting neuron [C. C. Canavier, J. W. Clark, and J. H. Byrne, J. Neurophysiol. 66, 2107-2124 (1991)] has been shown to possess seven coexisting limit cycle solutions at a given parameter set [Canavier et al., J. Neurophysiol 69, 2252-2259 (1993); 72, 872-882 (1994)]. These solutions are unique in that the limit cycles are concentric in the space of the slow variables. We examine the origin of these solutions using a minimal 4-variable bursting cell model. Poincaré maps are constructed using a saddle-node bifurcation of a fast subsystem such as our Poincaré section. This bifurcation defines a threshold between the active and silent phases of the burst cycle in the space of the slow variables. The maps identify parameter spaces with single limit cycles, multiple limit cycles, and two types of chaotic bursting. To investigate the dynamical features which underlie the unique shape of the maps, the maps are further decomposed into two submaps which describe the solution trajectories during the active and silent phases of a single burst. From these findings we postulate several necessary criteria for a bursting model to possess multiple stable concentric limit cycles. These criteria are demonstrated in a generalized 3-variable model. Finally, using a less direct numerical procedure, similar return maps are calculated for the original complex model [C. C. Canavier, J. W. Clark, and J. H. Byrne, J. Neurophysiol. 66, 2107-2124 (1991)], with the resulting mappings appearing qualitatively similar to those of our 4-variable model. These multistable concentric bursting solutions cannot occur in a bursting model with one slow variable. This type of multistability arises when a bursting system has two or more slow variables and is viewed as an essentially second-order system which receives discrete perturbations in a state-dependent manner.

  13. Personalized Medical Alert System

    Directory of Open Access Journals (Sweden)

    Juan Pablo Suarez Coloma

    2014-10-01

    Full Text Available The continuous increasing needs in telemedicine and healthcare, accentuate the need of well-adapted medical alert systems. Such alert systems may be used by a variety of patients and medical actors, and should allow monitoring a wide range of medical variables. This paper proposes Tempas, a personalized temporal alert system. It facilitates customized alert configuration by using linguistic trends. The trend detection algorithm is based on data normalization, time series segmentation, and segment classification. It improves state of the art by treating irregular and regular time series in an appropriate way, thanks to the introduction of an observation variable valid time. Alert detection is enriched with quality and applicability measures. They allow a personalized tuning of the system to help reducing false negatives and false positives alerts.

  14. THE BURST CLUSTER: DARK MATTER IN A CLUSTER MERGER ASSOCIATED WITH THE SHORT GAMMA-RAY BURST, GRB 050509B

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, H. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Sarazin, C. L. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Lopez, L. A. [MIT-Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-664H, Cambridge, MA 02139 (United States); Kouveliotou, C. [Space Science Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Patel, S. K. [Optical Sciences Corporation, 6767 Old Madison Pike, Suite 650, Huntsville, AL 35806 (United States); Rol, E.; Van der Horst, A. J.; Wijers, R. A. M. J. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam (Netherlands); Fynbo, J.; Michalowski, M. J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Burrows, D. N.; Grupe, D. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Gehrels, N. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ramirez-Ruiz, E., E-mail: hdahle@astro.uio.no [Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95060 (United States)

    2013-07-20

    We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster merger was discovered from observations of the first well-localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope error position of the source is coincident with a cluster of galaxies ZwCl 1234.0+02916, while the subsequent Swift/X-Ray Telescope localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained in this field to constrain the evolution of the GRB afterglow, including a total of 27,480 s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys, among the deepest imaging ever obtained toward a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis based on these data, including mapping of the total mass distribution of the merger system with high spatial resolution. When combined with Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and Swift/XRT observations, we are able to investigate the dynamical state of the merger to better understand the nature of the dark matter component. Our weak gravitational lensing measurements reveal a separation of the X-ray centroid of the western subcluster from the center of the mass and galaxy light distributions, which is somewhat similar to that of the famous 'Bullet cluster', and we conclude that this 'Burst cluster' adds another candidate to the previously known merger systems for determining the nature of dark matter, as well as for studying the environment of a short GRB. Finally, we discuss potential connections between the cluster dynamical state and/or matter composition, and compact object mergers, which is currently the leading model for the

  15. Localization of Gamma-Ray Bursts Using the Fermi Gamma-Ray Burst Monitor

    NARCIS (Netherlands)

    Connaughton, V.; Briggs, M.S.; Goldstein, A.; Meegan, C.A.; Paciesas, W.S.; Preece, R.D.; Wilson-Hodge, C.A.; Gibby, M.H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R.M.; Pelassa, V.; Xiong, S.; Yu, H-F.; Bhat, P.N.; Burgess, J.M.; Byrne, D.; Fitzpatrick, G.; Foley, S.; Giles, M.M.; Guiriec, S.; van der Horst, A.J.; von Kienlin, A.; McBreen, S.; McGlynn, S.; Tierney, D.; Zhang, B..B.

    2015-01-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the

  16. Herschel far-infrared photometry of the Swift Burst Alert Telescope active galactic nuclei sample of the local universe - III. Global star-forming properties and the lack of a connection to nuclear activity

    Science.gov (United States)

    Shimizu, T. Taro; Mushotzky, Richard F.; Meléndez, Marcio; Koss, Michael J.; Barger, Amy J.; Cowie, Lennox L.

    2017-04-01

    We combine the Herschel Space Observatory PACS (Photoconductor Array Camera and Spectrometer) and SPIRE (Spectral and Photometric Imaging Receiver) photometry with archival WISE (Wide-field Infrared Survey Explorer) photometry to construct the spectral energy distributions (SEDs) for over 300 local (z 0.5), especially at higher luminosities (L14 - 195 keV > 1042.5 erg s-1). Finally, we measure the local SFR-AGN luminosity relationship, finding a slope of 0.18, large scatter (0.37 dex), and no evidence for an upturn at high AGN luminosity. We conclude with a discussion on the implications of our results within the context of galaxy evolution with and without AGN feedback.

  17. Southern Fireworks above ESO Telescopes

    Science.gov (United States)

    1999-05-01

    And Transient Source Experiment (BATSE) onboard NASA's Compton Gamma-Ray Observatory (CGRO) high in orbit around the Earth, suddenly registered an intense burst of gamma-ray radiation from a direction less than 10° from the celestial south pole. Independently, the Gamma-Ray Burst Monitor (GRBM) on board the Italian-Dutch BeppoSAX satellite also detected the event (see GCN GRB Observation Report 304 [2]). Following the BATSE alert, the BeppoSAX Wide-Field Cameras (WFC) quickly localized the sky position of the burst within a circle of 3 arcmin radius in the southern constellation Chamaeleon. It was also detected by other satellites, including the ESA/NASA Ulysses spacecraft , since some years in a wide orbit around the Sun. The event was designated GRB 990510 and the measured position was immediately distributed by BeppoSAX Mission Scientist Luigi Piro to a network of astronomers. It was also published on Circular No. 7160 of the International Astronomical Union (IAU). From Amsterdam (The Netherlands), Paul Vreeswijk, Titus Galama , and Evert Rol of the Amsterdam/Huntsville GRB follow-up team (led by Jan van Paradijs ) immediately contacted astronomers at the 1-meter telescope of the South African Astronomical Observatory (SAAO) (Sutherland, South Africa) of the PLANET network microlensing team, an international network led by Penny Sackett in Groningen (The Netherlands). There, John Menzies of SAAO and Karen Pollard (University of Canterbury, New Zealand) were about to begin the last of their 14 nights of observations, part of a continuous world-wide monitoring program looking for evidence of planets around other stars. Other PLANET sites in Australia and Tasmania where it was still nighttime were unfortunately clouded out (some observations were in fact made that night at the Mount Stromlo observatory in Australia, but they were only announced one day later). As soon as possible - immediately after sundown and less than 9 hours after the initial burst was recorded

  18. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations

    Energy Technology Data Exchange (ETDEWEB)

    Ageron, Michel [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Al Samarai, Imen, E-mail: samarai@cppm.in2p3.fr [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Akerlof, Carl [Randall Laboratory of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109-1040 (United States); Basa, Stephane [LAM, BP8, Traverse du siphon, 13376 Marseille Cedex 12 (France); Bertin, Vincent [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Boer, Michel [OHP, 04870 Saint Michel de l' Observatoire (France); Brunner, Juergen; Busto, Jose; Dornic, Damien [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Klotz, Alain [OHP, 04870 Saint Michel de l' Observatoire (France); IRAP, 9 avenue du colonel Roche, 31028 Toulouse Cedex 4 (France); Schussler, Fabian; Vallage, Bertrand [CEA-IRFU, centre de Saclay, 91191 Gif-sur-Yvette (France); Vecchi, Manuela [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Zheng, Weikang [Randall Laboratory of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109-1040 (United States)

    2012-11-11

    The ANTARES telescope is well suited to detect neutrinos produced in astrophysical transient sources as it can observe a full hemisphere of the sky at all the times with a duty cycle close to unity and an angular resolution better than 0.5 Degree-Sign . Potential sources include gamma-ray bursts (GRBs), core collapse supernovae (SNe), and flaring active galactic nuclei (AGNs). To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated one or two times per month for special events such as two or more neutrinos coincident in time and direction or single neutrinos of very high energy. Since February 2009, ANTARES has sent 37 alert triggers to the TAROT and ROTSE telescope networks, 27 of them have been followed. First results on the optical images analysis to search for GRBs are presented.

  19. AlertSim - Serbian Contribution to the LSST

    Science.gov (United States)

    Jevremović, Darko; Vujčić, Veljko; Srećković, Vladimir A.; Aleksić, Jovan; Erkapić, Sanja; Milovanović, Nenad

    2017-06-01

    We present simulator of alerts for the Large Synoptic Survey Telescope (LSST) developed by Belgrade group. This simulator will be used in testing the functionality of external event brokers/Complex Event Processing (CEP) engines. It is based on current LSST Simulation framework and allows for different classes of objects to be `alerted'. A Web service based on our simulator is prototyped and can be accessed by developers of brokers/CEP engines.

  20. Medical alert bracelet (image)

    Science.gov (United States)

    People with diabetes should always wear a medical alert bracelet or necklace that emergency medical workers will be able to find. Medical identification products can help ensure proper treatment in an ...

  1. Alert Display Distribution (ADD)

    Data.gov (United States)

    Social Security Administration — Repository that contains alerts that will be sent to SSA employees when certain conditions exist, to inform them of work that needs to be done, is being reviewed, or...

  2. Alerts and Advisories

    Science.gov (United States)

    ... Trade Commission (FTC), to let consumers know about recalls, tainted products, and other alerts/advisories. 1 2 3 4 ... Treatments: FDA Warning - Fraudulent Claims of Diagnosis, Treatment, Prevention or Cure ( FDA 04/25/17 ) Organic Herbal ...

  3. DDBS DB Alert

    Data.gov (United States)

    Social Security Administration — Data store used by the database area for monitoring of database objects. It is used to generate alerts that the DBAs investigate to determine if any action needs to...

  4. Lower alert rates by clustering of related drug interaction alerts

    NARCIS (Netherlands)

    Heringa, M.; Siderius, H.; Floor-Schreudering, A.; Smet, P.A.G.M. de; Bouvy, M.L.

    2017-01-01

    OBJECTIVE: We aimed to investigate to what extent clustering of related drug interaction alerts (drug-drug and drug-disease interaction alerts) would decrease the alert rate in clinical decision support systems (CDSSs). METHODS: We conducted a retrospective analysis of drug interaction alerts

  5. Lower alert rates by clustering of related drug interaction alerts

    NARCIS (Netherlands)

    Heringa, M.; Siderius, Hidde; Schreudering, A.; De Smet, Peter Agm; Bouvy, M.L.

    OBJECTIVE: We aimed to investigate to what extent clustering of related drug interaction alerts (drug-drug and drug-disease interaction alerts) would decrease the alert rate in clinical decision support systems (CDSSs). METHODS: We conducted a retrospective analysis of drug interaction alerts

  6. 75 FR 67201 - Flightcrew Alerting

    Science.gov (United States)

    2010-11-02

    ... certain colors for advisory alerts. Weather displays and terrain awareness and warning system (TAWS) displays. Requiring cues from two different senses for warning and caution alerts. Identifying an alert and... conform to the following color convention (proposed Sec. 25.1322(d)): (1) Red for warning alert...

  7. Unusual Solar Decameter Radio Bursts with High Frequency Cut off

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. M.; Frantsuzenko, A. V.; Rucker, H. O.; Panchenko, M.

    2015-03-01

    Solar bursts with high frequency cut off were observed by the URAN-2 radio telescope (Poltava, Ukraine) on 18 August, 2012 in the frequency range 8-32 MHz. Durations of these bursts changed from 30 to 70 s. It is much longer than that for standard type III bursts. Drift rates are much smaller than those of type III bursts are, though much larger than those for decameter type II bursts. In some cases, the drift rate sign changes from the negative to positive one. Some of these bursts have fine structures. Stripes of the fine structures have small drift rates of 20-40 kHz/s. Polarizations of these bursts made about 10 % that apparently indicates that they are generated at the second harmonic of the local plasma frequency. The connection of bursts with the high frequency cut off with compact ejections from the behind-limb active regions is confirmed.

  8. Lower alert rates by clustering of related drug interaction alerts.

    Science.gov (United States)

    Heringa, Mette; Siderius, Hidde; Floor-Schreudering, Annemieke; de Smet, Peter A G M; Bouvy, Marcel L

    2017-01-01

    We aimed to investigate to what extent clustering of related drug interaction alerts (drug-drug and drug-disease interaction alerts) would decrease the alert rate in clinical decision support systems (CDSSs). We conducted a retrospective analysis of drug interaction alerts generated by CDSSs in community pharmacies. Frequently generated combinations of alerts were analyzed for associations in a 5% random data sample (dataset 1). Alert combinations with similar management recommendations were defined as clusters. The alert rate was assessed by simulating a CDSS generating 1 alert per cluster per patient instead of separate alerts. The simulation was performed in dataset 1 and replicated in another 5% data sample (dataset 2). Data were extracted from the CDSSs of 123 community pharmacies. Dataset 1 consisted of 841 572 dispensed prescriptions and 298 261 drug interaction alerts. Dataset 2 was comparable. Twenty-two frequently occurring alert combinations were identified. Analysis of these associated alert combinations for similar management recommendations resulted in 3 clusters (related to renal function, electrolytes, diabetes, and cardiovascular diseases). Using the clusters in alert generation reduced the alert rate within these clusters by 53-70%. The overall number of drug interaction alerts was reduced by 11% in dataset 1 and by 12% in dataset 2. This corresponds to a decrease of 21 alerts per pharmacy per day. Using clusters of drug interaction alerts with similar management recommendations in CDSSs can substantially decrease the overall alert rate. Further research is needed to establish the applicability of this concept in daily practice. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. UFFO/ Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

    Science.gov (United States)

    Park, I. H.; Panasyuk, M. I.; Reglero, V.; Chen, P.; Castro-Tirado, A. J.; Jeong, S.; Bogomolov, V.; Brandt, S.; Budtz-Jørgensen, C.; Chang, S.-H.; Chang, Y. Y.; Chen, C.-R.; Chen, C.-W.; Choi, H. S.; Connell, P.; Eyles, C.; Gaikov, G.; Garipov, G.; Huang, J.-J.; Huang, M.-H. A.; Jeong, H. M.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Lee, H. K.; Lee, J.; Lim, H.; Lin, C.-Y.; Liu, T.-C.; Nam, J. W.; Petrov, V.; Ripa, J.; Rodrigo, J. M.; Svertilov, S.; Wang, M.-Z.; Yashin, I.

    2018-02-01

    The payload of the UFFO (Ultra-Fast Flash Observatory)-pathfinder now onboard the Lomonosov spacecraft (hereafter UFFO/ Lomonosov) is a dedicated instrument for the observation of GRBs. Its primary aim is to capture the rise phase of the optical light curve, one of the least known aspects of GRBs. Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016, and will begin GRB observations after completion of functional checks of the Lomonosov spacecraft. The concept of early GRB photon measurements with UFFO was reported in 2012. In this article, we will report in detail the first mission, UFFO/Lomonosov, for the rapid response to GRB observations.

  10. Proxy magnetometry with the Dutch Open Telescope

    NARCIS (Netherlands)

    Rutten, R.J.; Hammerschlag, R.H.; Sütterlin, P.; Bettonvil, F.C.M.

    1999-01-01

    Superb movies from the Dutch Open Telescope (DOT) on La Palma have proven the validity of the open concept of this innovative telescope for high-resolution imaging of the solar atmosphere. A five- camera speckle-burst registration system is being installed that should permit consistent and

  11. Space Telescope.

    Science.gov (United States)

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)

  12. WindAlert

    OpenAIRE

    Raméntol Teys, David

    2016-01-01

    WindAlert és una aplicació per a dispositius Apple iPhone destinada als aficionats al Windsurf i/o al Kitesurf. La finalitat de l'aplicació és mantenir informats als seus usuaris de les condicions de vent a diferents punts del litoral, necessàries per a la pràctica de les activitats esmentades. WindAlert es una aplicación para dispositivos Apple iPhone destinada a los aficionados al Windsurf y/o al Kitesurf. La finalidad de la aplicación es mantener informados a sus usuarios de las condici...

  13. Alert status of nuclear weapons

    Science.gov (United States)

    Kristensen, Hans M.

    2017-11-01

    Nuclear Alert Forces. Four nuclear-armed states deploy nuclear warheads on alert, ready to be used on relatively short notice: United States, Russia, France and Britain. Combined, the four countries deploy an estimated 1,869 nuclear alert warheads. Russia and the United States deploy 1,749 alert warheads combined, or 94% of all alert warheads. Despite some debate about possible need to increase readiness of nuclear forces (China, Pakistan), the five other nuclear-armed states (China, Pakistan, India, Israel and North Korea) are thought to store their warheads separate from launchers under normal circumstances. The overall number of alert warheads has remained relatively stable during the past five years.

  14. Revisiting the Correlations of Peak Luminosity with Spectral Lag and Peak Energy of the Observed Gamma-ray Bursts

    Directory of Open Access Journals (Sweden)

    Yun-A Jo

    2016-12-01

    Full Text Available An analysis of light curves and spectra of observed gamma-ray bursts in gamma-ray ranges is frequently demanded because the prompt emission contains immediate details regarding the central engine of gamma-ray bursts (GRBs. We have revisited the relationship between the collimation-corrected peak luminosity and the spectral lag, investigating the lag-luminosity relationships in great detail by focusing on spectral lags resulting from all possible combinations of channels. Firstly, we compiled the opening angle data and demonstrated that the distribution of opening angles of 205 long GRBs is represented by a double Gaussian function having maxima at ~ 0.1 and ~ 0.3 radians. We confirmed that the peak luminosity and the spectral lag are anti-correlated, both in the observer frame and in the source frame. We found that, in agreement with our previous conclusion, the correlation coefficient improves significantly in the source frame. It should be noted that spectral lags involving channel 2 (25-50 keV yield high correlation coefficients, where Swift/Burst Alert Telescope (BAT has four energy channels (channel 1: 15-25 keV, channel 2: 25-50 keV, channel 3: 50-100 keV, channel 4: 100-200 keV. We also found that peak luminosity is positively correlated with peak energy.

  15. Modernizing emergency alerts poses challenges

    OpenAIRE

    Center for Homeland Defense and Security

    2010-01-01

    Center for Homeland Defense and Security, OUT OF THE CLASSROOM Download the paper: Paper: IPAWS (Integrated Public Alert and Warning System)” Modernizing emergency alerts poses challenges Anthony Cox is interested in the next generation of emergency alert systems.Any television viewer...

  16. The First Fermi-LAT Gamma-Ray Burst Catalog

    NARCIS (Netherlands)

    Ackermann, M.; et al., [Unknown; van der Horst, A.J.

    2013-01-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (gsim 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected

  17. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    Energy Technology Data Exchange (ETDEWEB)

    Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Connaughton, V.; Bhat, P. N.; Briggs, M. S.; Preece, R. [CSPAR and Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Jenke, P.; Kouveliotou, C.; Wilson-Hodge, C. A. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, NL-1090-GE Amsterdam (Netherlands); Camero-Arranz, A.; Finger, M.; Paciesas, W. S. [Universities Space Research Association, Huntsville, AL 35805 (United States); Beklen, E. [Physics Department, Suleyman Demirel University, 32260 Isparta (Turkey); Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany)

    2012-12-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 {+-} 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

  18. Recalls, Market Withdrawals and Safety Alerts

    Science.gov (United States)

    ... Home Safety Recalls, Market Withdrawals, & Safety Alerts Recalls, Market Withdrawals, & Safety Alerts Share Tweet Linkedin Pin it ... Safety Alerts Archive. Sign up to receive Recalls, Market Withdrawals and Safety Alerts . * FDA Employees: Use Chrome ...

  19. ASKAP Joins the Hunt for Mysterious Bursts

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    A new telescope, the Australian Square Kilometre Array Pathfinder (ASKAP), has joined the search for energetic and elusive fast radio bursts. And in just a few days of looking, its already had success!Elusive TransientsThe Parkes radio telescope, which has detected all but five of the fast radio bursts published to date, has a very narrow field of view. [CSIRO]Fast radio bursts are mysterious millisecond-duration radio pulses that were first discovered around a decade ago. Since that time particularly in recent years weve made some progress toward the goal of localizing them. Were now fairly convinced that fast radio bursts come from outside of the galaxy, and yet theyre enormously bright orders of magnitude more luminous than any pulse seen from the Milky Way.Better identification of where these mysterious bursts come from would help us to determine what they are. But so far, weve discovered only around 30 such bursts, despite the fact that theyre estimated to occur at a rate of 3,000 events per day across the whole sky.Why are they so hard to find? Due to their short duration, effective detection would require instantaneous coverage of a very large fraction of the sky. The Parkes radio telescope which has detected all but five of the fast radio bursts published to date has a field of view spanning less than a square degree,significantly limiting our ability to rapidly survey for these transients.FRB 170107s band-averaged pulse (top) and dynamic spectrum (bottom). [Bannister et al. 2017]A New Array in TownA new player is now on the scene, however, and its already had huge success. ASKAP is a wide-field radio telescope made up of an array of 12-meter antennas. Using phased-array-feed technology, ASKAP is able to instantaneously observe an effective area of 160 square degrees an enormous field compared to Parkes 0.6 square degrees! This capability significantly increases our chances of being able to detect fast radio bursts.In a new study led by Keith Bannister

  20. Gamma-ray bursts observed by the watch experiment

    DEFF Research Database (Denmark)

    Lund, Niels; Brandt, Søren; Castro-Tirado, A. J.

    1991-01-01

    After two years in orbit the WATCH instruments on the GRANAT space observatory have localized seven gamma burst sources with better than 1° accuracy. In several cases, follow‐up observations with Schmidt telescopes have been made within a few days. Some of the bursts have also been detected by th...... by the distant space probes PVO and ULYSSES and there are, therefore, good prospects for obtaining much improved positions using the burst arrival times. The existence of the almost concurrent Schmidt plates could then become particularly interesting.......After two years in orbit the WATCH instruments on the GRANAT space observatory have localized seven gamma burst sources with better than 1° accuracy. In several cases, follow‐up observations with Schmidt telescopes have been made within a few days. Some of the bursts have also been detected...

  1. The LOFT Burst Alert System and its Burst On-board Trigger

    DEFF Research Database (Denmark)

    Schanne, Stephane; Götz, Diego; Provost, Herve Le

    2014-01-01

    The ESA M3 candidate mission LOFT (Large Observatory For x-ray Timing) has been designed to study strong gravitational fields by observing compact objects, such as black-hole binaries or neutron-star systems and supermassive black-holes, based on the temporal analysis of photons collected by the ...

  2. The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows at 15.7 GHz

    Science.gov (United States)

    Anderson, G. E.; Staley, T. D.; van der Horst, A. J.; Fender, R. P.; Rowlinson, A.; Mooley, K. P.; Broderick, J. W.; Wijers, R. A. M. J.; Rumsey, C.; Titterington, D. J.

    2018-01-01

    We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7 GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target within 2 min, scheduling later start times if the source is below the horizon. Further AMI observations are manually scheduled for several days following the trigger. The AMI GRB programme probes the early-time (GRBs, and has obtained some of the earliest radio detections (GRB 130427A at 0.36 and GRB 130907A at 0.51 d post-burst). As all Swift GRBs visible to AMI are observed, this catalogue provides the first representative sample of GRB radio properties, unbiased by multiwavelength selection criteria. We report the detection of six GRB radio afterglows that were not previously detected by other radio telescopes, increasing the rate of radio detections by 50 per cent over an 18-month period. The AMI catalogue implies a Swift GRB radio detection rate of ≳ 15 per cent, down to ∼0.2 mJy beam-1. However, scaling this by the fraction of GRBs AMI would have detected in the Chandra & Frail sample (all radio-observed GRBs between 1997 and 2011), it is possible ∼ 44-56 per cent of Swift GRBs are radio bright, down to ∼0.1-0.15 mJy beam-1. This increase from the Chandra & Frail rate (∼30 per cent) is likely due to the AMI rapid-response mode, which allows observations to begin while the reverse-shock is contributing to the radio afterglow.

  3. ESA's Integral detects closest cosmic gamma-ray burst

    Science.gov (United States)

    2004-08-01

    should emit similar amounts of gamma-ray energy. The fraction of it detected at Earth should then depend on the 'width' (opening angle) and orientation of the beam as well as on the distance. The energy received should be larger when the beam is narrow or points towards us and smaller when the beam is broad or points away from us. New data collected with ESA's high energy observatories, Integral and XMM-Newton, now show that this picture is not so clear-cut and that the amount of energy emitted by GRBs can vary significantly. "The idea that all GRBs spit out the same amount of gamma rays, or that they are 'standard candles' as we call them, is simply ruled out by the new data," said Dr Sergey Sazonov, from the Space Research Institute of the Russian Academy of Sciences, Moscow (Russia) and the Max-Planck Institute for Astrophysics, Garching near Munich (Germany). Sazonov and an international team of researchers studied the GRB detected by Integral on 3 December 2003 and given the code-name of GRB 031203. Within a record 18 seconds of the burst, the Integral Burst Alert System had pinpointed the approximate position of GRB 031203 in the sky and sent the information to a network of observatories around the world. A few hours later one of them, ESA's XMM-Newton, determined a much more precise position for GRB 031203 and detected a rapidly fading X-ray source, which was subsequently seen by radio and optical telescopes on the ground. This wealth of data allowed astronomers to determine that GRB 031203 went off in a galaxy less than 1300 million light years away, making it the closest GRB ever observed. Even so, the way in which GRB 031203 dimmed with time and the distribution of its energy were not different from those of distant GRBs. Then, scientists started to realise that the concept of the 'standard candle' may not hold. "Being so close should make GRB 031203 appear very bright, but the amount of gamma-rays measured by Integral is about one thousand times less than what

  4. Gamma-Ray Bursts: A Radio Perspective

    Directory of Open Access Journals (Sweden)

    Poonam Chandra

    2016-01-01

    Full Text Available Gamma-ray bursts (GRBs are extremely energetic events at cosmological distances. They provide unique laboratory to investigate fundamental physical processes under extreme conditions. Due to extreme luminosities, GRBs are detectable at very high redshifts and potential tracers of cosmic star formation rate at early epoch. While the launch of Swift and Fermi has increased our understanding of GRBs tremendously, many new questions have opened up. Radio observations of GRBs uniquely probe the energetics and environments of the explosion. However, currently only 30% of the bursts are detected in radio bands. Radio observations with upcoming sensitive telescopes will potentially increase the sample size significantly and allow one to follow the individual bursts for a much longer duration and be able to answer some of the important issues related to true calorimetry, reverse shock emission, and environments around the massive stars exploding as GRBs in the early Universe.

  5. SNAP telescope

    Energy Technology Data Exchange (ETDEWEB)

    Lampton, Michael L.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Bercovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro, R.; Ealet, A.; Ellis,R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar,A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland,S.E.; Huterer, D.; Karcher, A.; Kim, A.G.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder, E.V.; Loken,S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi,H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto,E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.; Wang, G.

    2002-07-29

    The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.

  6. Space Telescopes

    Science.gov (United States)

    Rigby, Jane R.

    2011-01-01

    The science of astronomy depends on modern-day temples called telescopes. Astronomers make pilgrimages to remote mountaintops where these large, intricate, precise machines gather light that rains down from the Universe. Bit, since Earth is a bright, turbulent planet, our finest telescopes are those that have been launched into the dark stillness of space. These space telescopes, named after heroes of astronomy (Hubble, Chandra, Spitzer, Herschel), are some of the best ideas our species has ever had. They show us, over 13 billion years of cosmic history, how galaxies and quasars evolve. They study planets orbiting other stars. They've helped us determine that 95% of the Universe is of unknown composition. In short, they tell us about our place in the Universe. The next step in this journey is the James Webb Space Telescope, being built by NASA, Europe, and Canada for a 2018 launch; Webb will reveal the first galaxies that ever formed.

  7. Space Telescopes

    Science.gov (United States)

    2010-01-01

    Proc 6317:OT1–OT9 Serlemitsos PJ, Jahota L, Soong Y (plus 14 authors) (1995) The X-ray telescope on board ASCA. Pub Astron Soc Jap 47:105–114...Serlemitsos PJ, Soong Y, Chan K-W (plus 31 authors) (2007) The X-ray telescope on board Suzaku. Pub Astron Soc Jap 59:9–21 Shimizu T (2004) Solar-B solar

  8. Gamma-Ray Bursts and Cosmology

    Science.gov (United States)

    Norris, Jay P.

    2003-01-01

    The unrivalled, extreme luminosities of gamma-ray bursts (GRBs) make them the favored beacons for sampling the high redshift Universe. To employ GRBs to study the cosmic terrain -- e.g., star and galaxy formation history -- GRB luminosities must be calibrated, and the luminosity function versus redshift must be measured or inferred. Several nascent relationships between gamma-ray temporal or spectral indicators and luminosity or total energy have been reported. These measures promise to further our understanding of GRBs once the connections between the luminosity indicators and GRB jets and emission mechanisms are better elucidated. The current distribution of 33 redshifts determined from host galaxies and afterglows peaks near z $\\sim$ 1, whereas for the full BATSE sample of long bursts, the lag-luminosity relation predicts a broad peak z $\\sim$ 1--4 with a tail to z $\\sim$ 20, in rough agreement with theoretical models based on star formation considerations. For some GRB subclasses and apparently related phenomena -- short bursts, long-lag bursts, and X-ray flashes -- the present information on their redshift distributions is sparse or entirely lacking, and progress is expected in Swift era when prompt alerts become numerous.

  9. Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor

    OpenAIRE

    Connaughton, V.; Briggs, M. S.; Goldstein, A.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Wilson-Hodge, C.A.; Gibby, M. H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R. M.; Pelassa, V.; Xiong, S.; Yu, H-F

    2014-01-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 Gamma-Ray Bursts (GRBs) since it began science operations in July, 2008. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network (IPN), to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1 degree, underestimat...

  10. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  11. Observations of the Three Harmonic Components of Solar Type III Bursts at Decameter Wavelengths

    Science.gov (United States)

    Brazhenko, A. I.; Pylaev, O. S.; Melnik, V. M.; Konovalenko, O. O.; Frantsuzenko, A. V.; Dorovskyy, V. V.; Vashchishin, R. V.; Rucker, H. O.

    2013-12-01

    Triple type III bursts (combinations of three type III or type IIIb, bursts) with the frequency ratio of radiant flux maxima at a certain, point of time of approx. 1: 2 :3 are presented. Observations were, made with the URAN-2 radio telescope at 8 to 32 MHz. Main, characteristics of the components of triple bursts, such as duration,, drift rate, polarization, are studied. Also, the dependences, of the mentioned parameters on frequency, burst type and component, position within the triplet are discussed. The existence, of harmonic relation of the triple burst components is discussed.

  12. BATSE Observations of Gamma-Ray Burst Tails

    Science.gov (United States)

    Connaughton, Valerie

    2002-01-01

    With the observation of low-energy radiation coming from the site of gamma-ray bursts in the hours to weeks after the initial gamma ray burst, it appears that astronomers have discovered a cosmological imprint made by the burster on its surroundings. This paper discusses the phenomenon of postburst emission in Burst and Transient Source Experiment (BATSE) gamma-ray bursts at energies usually associated with prompt emission. After summing up the background-subtracted signals from hundreds of bursts, it is found that tails out to hundreds of seconds after the trigger could be a common feature of events of a duration greater than 2 seconds, and perhaps of the shorter bursts at a lower and shorter-lived level. The tail component may be softer and seems independent of the duration (within the long-GRB sample) and brightness of the prompt burst emission. Some individual bursts have visible tails at gamma-ray energies, and the spectrum in a few cases differs from that of the prompt emission. For one of these bursts, GRB 991216, afterglow at lower energies was detected, which raised the possibility of seeing afterglow observations over large energy ranges using the next generation of GRB detectors in addition to sensitive space- or ground-based telescopes.

  13. Adaptive Optical Burst Switching

    OpenAIRE

    Bonald, Thomas; Indre, Raluca-Maria; Oueslati, Sara

    2012-01-01

    International audience; We propose a modified version of Optical Burst Switching (OBS) that adapts the size of switched data units to the network load. Specifically, we propose a two-way reservation OBS scheme in which every active source-destination pair attempts to reserve a lightpath and for every successful reservation, transmits an optical burst whose size is proportional to the number of active data flows. We refer to this technique as Adaptive Optical Burst Switching. We prove that the...

  14. Radiation Alert Immediate Disclosure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Invocon's Radiation Alert Immediate Disclosure (RAID) system is a miniature, low-power, real-time, active radiation badge. It is designed for monitoring personnel,...

  15. Overview of the SVOM Gamma-Ray Burst mission under development with a focus on its Trigger system

    Science.gov (United States)

    Schanne, Stephane

    2017-08-01

    The SVOM mission (Space-based Variable Objects Monitor) is a Chinese-French satellite mission under development, devoted to collecting a complete sample of Gamma-Ray Bursts (GRBs) observed at multi-wavelengths with a high fraction of redshift determinations. In January 2017 the mission entered Phase C, starting officially construction, and the launch is foreseen in 2021. The SVOM satellite is equipped with 4 instruments, 2 of which cover the prompt GRB phase. The ECLAIRs coded-mask imager surveys a 2-sr large portion of the sky in the 4-150 keV energy range, well suited for the detection of X-ray rich and highly redshifted GRBs. The ECLAIRs trigger system continuously searches for GRBs using two algorithms, a count-rate trigger for short time scales and an image trigger for long time scales. In case of a localized new GRB candidate or a bright outburst of a known source, it promptly requests a satellite slew and sends an alert to ground. The onboard GRM (Gamma-Ray Monitor) extends the prompt energy coverage up to 5 MeV. After slew, 2 more onboard instruments study the GRB afterglow and refine the GRB localization: the MXT (Multi-pore optics X-ray Telescope) and the VT (Visible Telescope). Two types of ground telescopes are dedicated to SVOM. The GFTs (Ground Follow-up Telescopes) repoint autonomously to GRB alerts, refine their localization and provide photometric redshift. The SVOM observing strategy with roughly antisolar pointing combined with Galactic plane avoidance, ensures that most GRBs are quickly visible by the GFTs and large spectroscopic telescopes. The GWAC (Ground Wide Angle Camera) will observe the sky simultaneously with ECLAIRs to detect prompt optical GRB emissions. Today part of the GWAC is already operational. The SVOM GRB program is complemented by pre-planned target observations and ground-commanded targets of opportunity, e.g. to search for electromagnetic counterparts of gravity-wave events. On behalf of the SVOM and ECLAIRs teams, this

  16. A new CERN Alerter mechanism

    CERN Multimedia

    2007-01-01

    A new version of the CERN Alerter used for sending urgent messages was installed in July on all centrally managed NICE computers. This latest version is based on RSS (Really Simple Syndication) and all alerts are now displayed in an Internet Explorer window (see the picture). You can print the window by right-clicking on the alert background and selecting the Print option from the menu. If the message is not urgent, then the alert will only appear as a "balloon" window the following morning or at next logon. Non-Windows computers can also subscribe to this service by using their browser as an RSS reader (Really Simple Syndication). All recent web browsers can act as RSS readers, including Firefox and Safari. Simply subscribe to the following RSS feed: http://cern.ch/cernalerts/alerts.aspx to see all messages sent by the central services. More information on the CERN Alerter is available at: https://cern.ch/winservices/Help/?kbid=060810. Documentation on reading RSS feeds fr...

  17. A new CERN Alerter mechanism

    CERN Multimedia

    2007-01-01

    A new version of the CERN Alerter used for sending urgent messages was installed in July on all centrally managed NICE computers. This latest version is based on RSS (Really Simple Syndication) and all alerts are now displayed in an Internet Explorer window (see picture). You can print the window by right-clicking on the alert background and selecting the Print option from the menu. If the message is not urgent, the alert will only appear as a "balloon" window the following morning or at next log-on. Non-Windows computers can also subscribe to this service by using their browser as an RSS reader. All recent web browsers can act as RSS readers, including Firefox and Safari. Simply subscribe to the following RSS feed: http://cern.ch/cernalerts/alerts.aspx to see all messages sent by the central services. More information on the CERN Alerter is available at: https://cern.ch/winservices/Help/?kbid=060810. Documentation on reading RSS fee...

  18. Observations of gamma-ray burst afterglows with the AEOS Burst Camera

    Science.gov (United States)

    Flewelling, Heather Anne

    Gamma-ray bursts (GRBs), are variable bursts of gamma-ray radiation, that lasts from milliseconds to hundreds of seconds. These bursts of gamma rays are detected in other wavelengths (optical, IR, radio, X-ray), because the afterglow lasts much longer, and this enables us to learn more about GRBs. The AEOS Burst Camera (ABC) is a 6'x6' field of view camera designed to observe the optical afterglows of GRBs, and is mounted on the 3.67m Advanced Electro- Optical System (AEOS) telescope, located at 10,000ft on Haleakala, Hawaii. There are 45 hours of Target of Opportunity (ToO) time to observe GRBs detected by Swift and other GRB satellites. Observations are started within minutes after a suitable GRB is detected, and continue for an hour or two. During this project, 21 GRBs were observed, and of those, 10 had detected afterglows, and 4 had interesting limits. About half of the bursts fit the fireball model, and half did not, which is similar to what ROTSE has found. Roughly half of the ABC bursts fall in the dark category, with b ox Akerlof Sr, Swan (2007) found, that roughly 70% of all GRBs brighter than 22nd mag at 1000s should be detectable.

  19. Optical polarimetric observations of GRB prompt emissions by MASTER robots-telescopes net.

    Science.gov (United States)

    Gorbovskoy, Evgeny; Lipunov, Vladimir; Kornilov, Victor; Shatskij, Nikolaj; Kuvshi-Nov, Dmitry; Tyurina, Nataly; Belinski, Alexander; Krylov, Alexander; Balanutsa, Pavel; Chazov, Vadim; Kuznetsov, Artem; Zimnuhov, Dmitry; Balanutsa, Pavel; Kortunov, Petr; Sankovich, Anatoly; Tlatov, An-Drey; Parkhomenko, A.; Krushinsky, Vadim; Zalozhnyh, Ivan; Popov, A.; Kopytova, Taisia; Ivanov, Kirill; Yazev, Sergey; Yurkov, Vladimir

    The main goal of the MASTER-Net project is to produce a unique fast sky survey with all sky observed over a single night down to a limiting magnitude of 19 -20mag. Such a survey will make it possible to address a number of fundamental problems: search for dark energy via the discovery and photometry of supernovas (including SNIa), search for exoplanets, microlensing effects, discovery of minor bodies in the Solar System and space-junk monitoring. All MASTER telescopes can be guided by alerts, and we plan to observe prompt optical emission from gamma-ray bursts synchronously in several filters and in several polarization planes. Observations on telescopes capable to observ polarisation of GRB prompt emission have been begun in the summer of 2009. Since summer of 2009 an observations of several GRB have been made. In particular for GRB0910 and GRB091127 optical polarisation has been measured. So, for GRB091127 which supervision have begun all through 91 sec polarisation at level of several tens percent has been registered. (GCN 10231, GCN 10052, GCN 10203)

  20. Global Environmental Alert Service

    Science.gov (United States)

    Grasso, V. F.; Cervone, G.; Singh, A.; Kafatos, M.

    2006-12-01

    Environmental Alert Service (GEAS) that could provide information from monitoring, Earth observing and early warning systems to users in a near real time mode and bridge the gap between the scientific community and policy makers. Characteristics and operational aspects of GEAS are discussed.

  1. The impact of the in-orbit background and the X-ray source intensity on the centroiding accuracy of the Swift X-ray telescope

    CERN Document Server

    Ambrosi, R M; Hill, J; Cheruvu, C; Abbey, A F; Short, A D T

    2002-01-01

    The optical components of the Swift Gamma Ray Burst Explorer X-ray Telescope (XRT), consisting of the JET-X spare flight mirror and a charge coupled device of the type used in the EPIC program, were used in a re-calibration study carried out at the Panter facility, which is part of the Max Planck Institute for Extraterrestrial Physics. The objective of this study was to check the focal length and the off axis performance of the mirrors and to show that the half energy width (HEW) of the on-axis point spread function (PSF) was of the order of 16 arcsec at 1.5 keV (Nucl. Instr. and Meth. A 488 (2002) 543; SPIE 4140 (2000) 64) and that a centroiding accuracy better that 1 arcsec could be achieved within the 4 arcmin sampling area designated by the Burst Alert Telescope (Nucl. Instr. and Meth. A 488 (2002) 543). The centroiding accuracy of the Swift XRT's optical components was tested as a function of distance from the focus and off axis position of the PSF (Nucl. Instr. and Meth. A 488 (2002) 543). The presence ...

  2. Detection of the optical afterglow of GRB 000630: Implications for dark bursts

    DEFF Research Database (Denmark)

    Fynbo, J.U.; Jensen, B.L.; Gorosabel, J.

    2001-01-01

    We present the discovery of the optical transient of the long-duration gamma-ray burst GRB 000630. The optical transient was detected with the Nordic Optical Telescope 21.1 hours after the burst. At the time of discovery the magnitude of the transient was R = 23.04 +/- 0.08. The transient display...

  3. The Drift Burst Hypothesis

    DEFF Research Database (Denmark)

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    The Drift Burst Hypothesis postulates the existence of short-lived locally explosive trends in the price paths of financial assets. The recent US equity and Treasury flash crashes can be viewed as two high profile manifestations of such dynamics, but we argue that drift bursts of varying magnitude....... We then develop a non-parametric test statistic that allows for the identification of drift bursts from noisy high-frequency data. We apply this methodology to a comprehensive set of tick data and show that drift bursts form an integral part of the price dynamics across equities, fixed income......, currencies and commodities. We find that the majority of identified drift bursts are accompanied by strong price reversals and these can therefore be regarded as “flash crashes” that span brief periods of severe market disruption without any material longer term price impacts....

  4. Fast radio burst tied to distant dwarf galaxy (Image 2)

    National Science Foundation

    2017-06-07

    Full Text Available Radio telescope at Arecibo only localized the fast radio burst to the area inside the two circles in this image, but the Very Large Array was able to pinpoint it as a dwarf galaxy within the square (shown at intersection of cross hairs in enlarged box)

  5. The NuSTAR View of Gamma Ray Bursts

    Science.gov (United States)

    Kouveliotou, C.

    2014-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) mission was launched June 13, 2012. During the next two pears NuSTAR observed two Gamma Ray Bursts, GRBs 130427A and 130925A. I will describe here the NuSTAR GRB results and discuss their implications on the GRB field.

  6. Detection of GRB 060927 at z = 5.47: Implications for the Use of Gamma-Ray Bursts as Probes of the End of the Dark Ages

    NARCIS (Netherlands)

    Ruiz-Velasco, A.E.; Swan, H.; Troja, E.; Malesani, D.; Fynbo, J.P.U.; Starling, R.L.C.; Xu, D.; Aharonian, F.; Akerlof, C.; Andersen, M.I.; Ashley, M.C.B.; Barthelmy, S.D.; Bersier, D.F.; Cerón, J.M.; Castro-Tirado, A.J.; Gehrels, N.; Gögüs, E.; Gorosabel, J.; Guidorzi, C.; Güver, T.; Hjorth, J.; Horns, D.; Huang, K.Y.; Jakobsson, P.; Jensen, B.L.; Kiziloglu, Ü.; Kouveliotou, C.; Krimm, H.A.; Ledoux, C.; Levan, A.J.; Marsh, T.; McKay, T.; Melandri, A.; Milvang-Jensen, B.; Mundell, C.G.; O'Brien, P.T.; Özel, M.; Phillips, A.; Quimby, R.; Rowell, G.; Rujopakarn, W.; Rykoff, E.S.; Schaefer, B.E.; Sollerman, J.; Tanvir, N.R.; Thöne, C.C.; Urata, Y.; Vestrand, W.T.; Vreeswijk, P.M.; Watson, D.; Wheeler, J.C.; Wijers, R.A.M.J.; Wren, J.; Yost, S.A.; Yuan, F.; Zhai, M.; Zheng, W.K.

    2007-01-01

    We report on follow-up observations of the gamma-ray burst GRB 060927 using the robotic ROTSE-IIIa telescope and a suite of larger aperture ground-based telescopes. An optical afterglow was detected 20 s after the burst, the earliest rest-frame detection of optical emission from any GRB.

  7. INTEGRAL Results on Gamma-Ray Bursts

    Science.gov (United States)

    Hurley, Kevin C.

    2008-03-01

    Prompt, precise localizations of gamma-ray bursts imaged by IBIS are being disseminated at a rate of about 10 per year (49 to date). The INTEGRAL Burst Alert System (IBAS) produces automated alerts within 10's of seconds, giving positions which are accurate to several arcminutes for events as weak as 5.7 x 10-8 erg cm-2. IBIS is also a very sensitive detector of soft gamma repeaters (SGRs). It has detected well over 200 bursts from SGR1806-20, down to a fluence of 7×10-9 erg cm-2. An unexpected discovery is that the quiescent X-ray emission of this source and SGR 1900+14 is considerably harder than previous measurements indicated, and extends to 200 keV, a property which SGRs share with the AXP's. In addition, the SPI anti-coincidence shield (ACS) system is an extremely useful component of the interplanetary network. With its isotropic response, it detects about 66 confirmed bursts/year ( 450 to date) down to a threshold of 4.8×10-8 erg cm-2, many of which can be localized by triangulation. Most of these events are not detected by Swift or IBIS due to their limited fields of view. The triangulation results are currently being used to search for coincident neutrino emission, for gravitational radiation simultaneous with GRBs, and for coincidences between Type Ic supernovae and bursts, among other things. The SPI ACS has recently played a key role in localizing and identifying two events which are believed to be extragalactic giant magnetar flares (EMFs), from M81 and M31. LIGO was operating at the time of one of these events, and their observations support the EMF hypothesis. SPI is also being used as a Compton-scatter polarimeter for GRBs. Kalemci et al. (2007) and McGlynn et al. (2007) studied its response to GRB041219a, and obtained polarizations of 98% +/- 33%, and 63% (+31%,-30%) respectively.

  8. The Chase to Capture Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil

    2008-01-01

    Gamma-ray bursts are the most powerful explosions in the universe, thought to be the birth cries of black holes. It has taken 40 years of international cooperation and competition to begin to unravel the mystery of their origin. The most recent chapter in this field is being written by the SWIFT mission, a fast-response satellite with 3 power telescopes. An international team from countries all over the world participates in the chase to capture the fading light of bursts detected by SWIFT. This talk will discuss the challenges and excitement of building this space observatory. New results will be presented on our growing understanding of exploding stars and fiery mergers of orbiting stars.

  9. Core-Collapse Supernovae and Gamma-Ray Bursts in TMT Era

    Indian Academy of Sciences (India)

    Existing 8–10 m class telescopes have been helpful to improve our knowledge about core-collapse supernovae, gamma-ray bursts and nature of their progenitors and explosion mechanisms. However, many aspects about these energetic cosmic explosions are still not well-understood and require much bigger telescopes ...

  10. Gamma-ray bursts

    National Research Council Canada - National Science Library

    Gehrels, Neil; Mészáros, Péter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe...

  11. An Unusual Burst at Decameter Wavelengths. 1. Observations

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. M.; Konovalenko, O. O.; Dorovskyy, V. V.; Frantsuzenko, A. V.; Rucker, H. O.; Panchenko, M.; Stanislavsky, A. A.

    2012-06-01

    An unusual burst was observed by the UTR-2 (Kharkiv, Ukraine) and URAN-2 (Poltava, Ukraine) radio telescopes on June 3, 2011. It was recorded in the frequency band 16-28 MHz. Its frequency drift rate (about 500 kHz/s) was positive at frequencies higher than 22 MHz and negative with drift rate 100 kHz/s at lower frequencies. The half-power duration of this burst was about the same at all frequencies and made 17-22 s. The fine frequency-time structure was unusual too. The maximum radio flux of the unusual burst at 24 MHz was about 103 s.f.u. and its polarization was about 10 %. We propose an interpretation of the unusual burst.

  12. The Montsec Observatory and the Gaia science alerts

    Science.gov (United States)

    Carrasco, J. M.; Burgaz, U.; Vilardell, F.; Jordi, C.

    2017-03-01

    The continuous and reiterative scan of the whole sky performed by Gaia ESA's mission during its (at least) 5 years of mission allows to detect transient events (e.g., supernovae, microlensing events, cataclysmic variables, etc) almost in real time among the daily millions of observations. The pipeline in charge to discover these alerts does a quick look analysis of the daily data stream, identify those sources increasing their brightness with respect to previous Gaia observations and also analyse their spectrophotometry to decide if those sources are good candidates to be published as a Gaia Photometric Science Alerts. These events are publicly announced for follow-up observations (both photometric and spectroscopic are needed). Observatories around the world confirm, classify and study them in detail. Observations are put in common and analysed together in a common interface in order to get a single analysis as detailed and precise as possible. Our team in Barcelona contributes to this Gaia science alerts follow-up programme with the 0.8 m robotic telescope Joan Oró (TJO), at the Montsec Observatory (OAdM), located at Sant Esteve de la Sarga (Lleida, Spain) performing photometric observations to derive the lightcurves of the most interesting alerts accessible from the observatory. Until now we have contributed with about 4500 images in multicolour Johnson-Cousins passbands obtained with TJO for a total of 38 Gaia science alerts, becoming the third most contributing observatory in the programme. Here we summarise the procedure to select new targets to be observed by TJO, submit follow-up observations and we explain the analysis we did for some interesting obtained lightcurves.

  13. Ground-based and spaceborn observations of the type II burst with developed fine structure

    Science.gov (United States)

    Dorovskyy, V.; Melnik, V.; Konovalenko, A.; Brazhenko, A.; Rucker, H.; Stanislavskyy, A.; Panchenko, M.

    2012-09-01

    The combination of two huge ground-based radio telescopes (UTR-2 and URAN-2) operated in decameter wavelengths with three spatially separated spacecrafts (SOHO, STEREO-A and STEREO-B) equipped with white light coronagraphs, UV telescopes and decameter-hectometer band radio telescopes created a unique opportunity to investigate the high energy solar transients, such as CMEs and their manifestations in radio bands - type II bursts. In this paper we made detailed analysis of the powerful and complex event occurred on 7 June 2011 consisted of Halo-CME and type II burst with rich fine structure.

  14. 21 CFR 26.20 - Alert system.

    Science.gov (United States)

    2010-04-01

    ... PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN... Provisions for Pharmaceutical Good Manufacturing Practices § 26.20 Alert system. (a) The details of an alert...

  15. Unusual Solar Radio Burst Observed at Decameter Wavelengths

    Science.gov (United States)

    Melnik, V. N.; Brazhenko, A. I.; Konovalenko, A. A.; Rucker, H. O.; Frantsuzenko, A. V.; Dorovskyy, V. V.; Panchenko, M.; Stanislavskyy, A. A.

    2014-01-01

    An unusual solar burst was observed simultaneously by two decameter radio telescopes UTR-2 (Kharkov, Ukraine) and URAN-2 (Poltava, Ukraine) on 3 June 2011 in the frequency range of 16 - 28 MHz. The observed radio burst had some unusual properties, which are not typical for the other types of solar radio bursts. Its frequency drift rate was positive (about 500 kHz s-1) at frequencies higher than 22 MHz and negative (100 kHz s-1) at lower frequencies. The full duration of this event varied from 50 s up to 80 s, depending on the frequency. The maximum radio flux of the unusual burst reached ≈103 s.f.u. and its polarization did not exceed 10 %. This burst had a fine frequency-time structure of unusual appearance. It consisted of stripes with the frequency bandwidth 300 - 400 kHz. We consider that several accompanied radio and optical events observed by SOHO and STEREO spacecraft were possibly associated with the reported radio burst. A model that may interpret the observed unusual solar radio burst is proposed.

  16. High Energy Astrophysics with the Fermi Large Area Telescope

    Science.gov (United States)

    Hays, Elizabeth

    2009-01-01

    This slide presentation reviews some of the findings of the Large Area Telescope (LAT) aboard the Fermi Observatory. It includes information about the LAT, and the Gamma-Ray Burst Monitor (GBM), detection of the quiet sun and the moon in gamma rays, Pulsars observed by the observatory, Globular Star Clusters, Active Galactic Nucleus, and Gamma-Ray Bursts, with specific information about GRB 080916C.

  17. 77 FR 41331 - Commercial Mobile Alert System

    Science.gov (United States)

    2012-07-13

    ... Warning, Alert, and Response Network (WARN) Act, Public Law 109-347, the Federal Communications Commission... COMMISSION 47 CFR Part 10 Commercial Mobile Alert System AGENCY: Federal Communications Commission. ACTION... collection requirements associated with the Commission's Commercial Mobile Alert System (CMS), Second Report...

  18. Study of neutrino production in the Cannonball model of Gamma ray bursts: possibility of observation of these neutrinos with the Antares neutrinos telescope, and study of the optical background recorded with the prototype sector line; Etude de la production de neutrinos associes aux Sursauts Gamma dans le modele du Boulet de canon: possibilite d'observation de ces neutrinos par le detecteur ANTARES, et etude du bruit de fond optique enregistre par le prototype d'un secteur de ligne

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, S

    2004-09-15

    ANTARES is a future neutrino telescope which will be build at 40 km off the french coast (Toulon), at a 2500 m depth. The interaction of a neutrino with matter produces a muon which emits Cerenkov light while propagating in water. This light is detected with 900 photomultipliers distributed over 12 lines. Gamma ray bursts (GRB) are violent cosmological phenomenon observed once per day. In the Cannonball Model, bursts are produced by the interaction of a jet made of cannonballs (CB) with a supernova remnant (SNR). Forward shocks propagate in the SNR, reverse ones in the CB and neutrinos are produced at the shock fronts. An estimation of the neutrino production is given and is studied over a large parameter range. For a typical GRB, 0.002 to 0.3 v{sub {mu}}, cm{sup -2} can be produced. Depending on the viewing angle, ANTARES could detect 1 to 10 v{sub {mu}} per year in correlation with GRBs. The ambient optical background has been recorded by the ANTARES prototype sector line. The analysis is about the background influence on the detector performance and about the organisms activity which produces it. For example, it appears a 17.6 to 20.4 h periodicity which is compatible with the liquid masses movement imposed by the Coriolis force at the ANTARES latitude. (author)

  19. Are There Multiple Populations of Fast Radio Bursts?

    Science.gov (United States)

    Palaniswamy, Divya; Li, Ye; Zhang, Bing

    2018-02-01

    The repeating FRB 121102 (the “repeater”) shows repetitive bursting activities and was localized in a host galaxy at z = 0.193. On the other hand, despite dozens of hours of telescope time spent on follow-up observations, no other fast radio bursts (FRBs) have been observed to repeat. Yet, it has been speculated that the repeater is the prototype of FRBs, and that other FRBs should show similar repeating patterns. Using the published data, we compare the repeater with other FRBs in the observed time interval (Δt)–flux ratio (S i /S i+1) plane. We find that whereas other FRBs occupy the upper (large S i /S i+1) and right (large Δt) regions of the plane due to the non-detections of other bursts, some of the repeater bursts fall into the lower left region of the plot (short interval and small flux ratio) excluded by the non-detection data of other FRBs. The trend also exists even if one only selects those bursts detectable by the Parkes radio telescope. If other FRBs were similar to the repeater, our simulations suggest that the probability that none of them have been detected to repeat with the current searches would be ∼(10‑4–10‑3). We suggest that the repeater is not representative of the entire FRB population, and that there is strong evidence of more than one population of FRBs.

  20. Holographic telescope

    Science.gov (United States)

    Odhner, Jefferson E.

    2016-07-01

    Holographic optical elements (HOEs) work on the principal of diffraction and can in some cases replace conventional optical elements that work on the principal of refraction. An HOE can be thinner, lighter, can have more functionality, and can be lower cost than conventional optics. An HOE can serve as a beam splitter, spectral filter, mirror, and lens all at the same time. For a single wavelength system, an HOE can be an ideal solution but they have not been widely accepted for multispectral systems because they suffer from severe chromatic aberration. A refractive optical system also suffers from chromatic aberration but it is generally not as severe. To color correct a conventional refractive optical system, a flint glass and a crown glass are placed together such that the color dispersion of the flint and the crown cancel each other out making an achromatic lens (achromat) and the wavelengths all focus to the same point. The color dispersion of refractive lenses and holographic lenses are opposite from each other. In a diffractive optical system, long wavelengths focus closer (remember for HOEs: RBM "red bends more") than nominal focus while shorter wavelengths focus further out. In a refractive optical system, it is just the opposite. For this reason, diffractives can be incorporated into a refractive system to do the color correction and often cut down on the number of optical elements used [1.]. Color correction can also be achieved with an all-diffractive system by combining a holographic optical element with its conjugate. In this way the color dispersion of the first holographic optical element can be cancelled by the color dispersion of the second holographic optic. It is this technique that will be exploited in this paper to design a telescope made entirely of holographic optical elements. This telescope could be more portable (for field operations) the same technique could be used to make optics light enough for incorporation into a UAV.

  1. Observing a Burst with Sunglasses

    Science.gov (United States)

    2003-11-01

    Unique Five-Week VLT Study of the Polarisation of a Gamma-Ray Burst Afterglow "Gamma-ray bursts (GRBs)" are certainly amongst the most dramatic events known in astrophysics. These short flashes of energetic gamma-rays, first detected in the late 1960's by military satellites, last from less than one second to several minutes. GRBs have been found to be situated at extremely large ("cosmological") distances. The energy released in a few seconds during such an event is larger than that of the Sun during its entire lifetime of more than 10,000 million years. The GRBs are indeed the most powerful events since the Big Bang known in the Universe, cf. ESO PR 08/99 and ESO PR 20/00. During the past years circumstantial evidence has mounted that GRBs signal the collapse of extremely massive stars, the so-called hypernovae. This was finally demonstrated some months ago when astronomers, using the FORS instrument on ESO's Very Large Telescope (VLT), documented in unprecedented detail the changes in the spectrum of the light source ("the optical afterglow") of the gamma-ray burst GRB 030329 (cf. ESO PR 16/03). A conclusive and direct link between cosmological gamma-ray bursts and explosions of very massive stars was provided on this occasion. Gamma-Ray Burst GRB 030329 was discovered on March 29, 2003 by NASA's High Energy Transient Explorer spacecraft. Follow-up observations with the UVES spectrograph at the 8.2-m VLT KUEYEN telescope at the Paranal Observatory (Chile) showed the burst to have a redshift of 0.1685 [1]. This corresponds to a distance of about 2,650 million light-years, making GRB 030329 the second-nearest long-duration GRB ever detected. The proximity of GRB 030329 resulted in very bright afterglow emission, permitting the most extensive follow-up observations of any afterglow to date. A team of astronomers [2] led by Jochen Greiner of the Max-Planck-Institut für extraterrestrische Physik (Germany) decided to make use of this unique opportunity to study the

  2. Limits on Neutrino Emission from Gamma-Ray Bursts with the 40 String IceCube Detector

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D.J.; Bohm, C.; Bose, D.; Boser, S.; Botner, O.; Braun, J.; Brown, A.M.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Daughhetee, J.; Davis, J.C.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dierckxsens, M.; Dreyer, J.; Dumm, J.P.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Herquet, P.; Hickford, S.; Lafebre, S.J.

    2011-01-01

    IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18) eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search

  3. Synchrotron cooling in energetic gamma-ray bursts observed by the Fermi Gamma-Ray Burst Monitor

    OpenAIRE

    Yu, Hoi Fung; Greiner, Jochen; van Eerten, Hendrik; Burgess, J. Michael; P. Narayana Bhat; Briggs, Michael S.; Connaughton, Valerie; Diehl, Roland; Goldstein, Adam; Gruber, David; Jenke, Peter A.; von Kienlin, Andreas; Kouveliotou, Chryssa; Paciesas, William S.; Pelassa, Veronique

    2015-01-01

    Context. We study the time-resolved spectral properties of energetic gamma-ray bursts (GRBs) with good high-energy photon statistics observed by the Gamma-Ray Burst Monitor (GBM) onboard the Fermi Gamma-Ray Space Telescope. Aims. We aim to constrain in detail the spectral properties of GRB prompt emission on a time-resolved basis and to discuss the theoretical implications of the fitting results in the context of various prompt emission models. Methods. Our sample comprises eight GRBs observe...

  4. Decameter Type III Bursts with Changing Frequency Drift-Rate Signs

    Science.gov (United States)

    Melnik, V. N.; Brazhenko, A. I.; Konovalenko, A. A.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Frantsuzenko, A. V.; Rucker, H. O.; Rutkevych, B. P.; Panchenko, M.; Denis, L.; Zaqarashvili, T.; Shergelashvili, B.

    2015-01-01

    We discuss properties of type III bursts that change the sign of their drift rate from negative to positive and vice versa. Moreover, these bursts may change the sign of their drift rates more than once. These particular type III bursts were observed simultaneously by the radio telescopes UTR-2 ( Ukrainian T-shaped Radio telescope, Kharkov, Ukraine), URAN-2 ( Ukrainian Radio telescope of the Academy of Sciences, Poltava, Ukraine), and by the NDA ( Nançay Decametric Array, Nancay, France) in the frequency range 8 - 41 MHz. The negative drift rates of these bursts are similar to those of previously reported decameter type III bursts and vary from -0.7 MHz s-1 to -1.7 MHz s-1, but their positive drift rates vary in a wider range from 0.44 MHz s-1 to 6 MHz s-1. Unlike inverted U-bursts, the tracks of these type III bursts have C- or inverted C-shapes.

  5. Alert Triage v 0.1 beta

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-06

    In the cyber security operations of a typical organization, data from multiple sources are monitored, and when certain conditions in the data are met, an alert is generated in an alert management system. Analysts inspect these alerts to decide if any deserve promotion to an event requiring further scrutiny. This triage process is manual, time-consuming, and detracts from the in-depth investigation of events. We have created a software system that uses supervised machine learning to automatically prioritize these alerts. In particular we utilize active learning to make efficient use of the pool of unlabeled alerts, thereby improving the performance of our ranking models over passive learning. We have demonstrated the effectiveness of our system on a large, real-world dataset of cyber security alerts.

  6. Alert dwell time: introduction of a measure to evaluate interruptive clinical decision support alerts.

    Science.gov (United States)

    McDaniel, Robert B; Burlison, Jonathan D; Baker, Donald K; Hasan, Murad; Robertson, Jennifer; Hartford, Christine; Howard, Scott C; Sablauer, Andras; Hoffman, James M

    2016-04-01

    Metrics for evaluating interruptive prescribing alerts have many limitations. Additional methods are needed to identify opportunities to improve alerting systems and prevent alert fatigue. In this study, the authors determined whether alert dwell time-the time elapsed from when an interruptive alert is generated to when it is dismissed-could be calculated by using historical alert data from log files. Drug-drug interaction (DDI) alerts from 3 years of electronic health record data were queried. Alert dwell time was calculated for 25,965 alerts, including 777 unique DDIs. The median alert dwell time was 8 s (range, 1-4913 s). Resident physicians had longer median alert dwell times than other prescribers (P dwell times than alerts that only occurred once (P < 001). This metric can be used in future research to evaluate the effectiveness and efficiency of interruptive prescribing alerts. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. An unusual burst at decameter wavelengths. 2. Interpretation

    Science.gov (United States)

    Melnik, V. M.; Brazhenko, A. I.; Konovalenko, O. O.; Dorovskyy, V. V.; Frantsuzenko, A. V.; Rucker, H. O.; Panchenko, M.; Stanislavsky, A. A.

    2012-09-01

    The model which describes appearance and process of radio emission of an unusual burst observed by the UTR-2 (Kharkiv, Ukraine) and URAN-2 (Poltava, Ukraine) radio telescopes at 16-28 MHz is proposed. We suppose that the unusual burst is caused by the small ejection initiated by the active region NOAA1222. This behind-limb region was situated at the heights 2.3R⊙⊙ to 2.8R to 2.8R⊙⊙, when radio emission of the unusual burst at the second harmonic was started. We believe that due to interaction of this ejection with coronal plasma some electrons were accelerated. These electrons propagating towards and outwards the Sun were sources of the UTR-2, URAN-2 and STEREO-A recorded unusual burst. The mechanism of radio emission was plasma one. The proposed model allows explaining such properties of the unusual burst as its positive and negative drift rates, duration, abrupt stopping of radio emission at 27.5 MHz and its fine frequency structure., when radio emission of the unusual burst at the second harmonic was started. We believe that due to interaction of this ejection with coronal plasma some electrons were accelerated. These electrons propagating towards and outwards the Sun were sources of the UTR-2, URAN-2 and STEREO-A recorded unusual burst. The mechanism of radio emission was plasma one. The proposed model allows explaining such properties of the unusual burst as its positive and negative drift rates, duration, abrupt stopping of radio emission at 27.5 MHz and its fine frequency structure.

  8. The High Energy Telescope on EXIST: The First Prototype of Advanced Imaging CZT Detectors

    Science.gov (United States)

    Hong, JaeSub; Allen, B.; Grindlay, J.; Barthelmy, S.; Gehrels, N.; Skinner, G.; Finger, M.; Jernigan, G.; EXIST Team

    2009-12-01

    The High Energy Telescope (HET) on EXIST is a coded-aperture telescope using a large array of CZT detectors and hybrid tungsten mask. The HET will locate high red-shift Gamma-Ray Bursts (GRBs) and other rare elusive transients quickly (EXIST.

  9. Gamma-ray bursts

    CERN Document Server

    Wijers, Ralph A M J; Woosley, Stan

    2012-01-01

    Cosmic gamma ray bursts (GRBs) have fascinated scientists and the public alike since their discovery in the late 1960s. Their story is told here by some of the scientists who participated in their discovery and, after many decades of false starts, solved the problem of their origin. Fourteen chapters by active researchers in the field present a detailed history of the discovery, a comprehensive theoretical description of GRB central engine and emission models, a discussion of GRB host galaxies and a guide to how GRBs can be used as cosmological tools. Observations are grouped into three sets from the satellites CGRO, BeppoSAX and Swift, and followed by a discussion of multi-wavelength observations. This is the first edited volume on GRB astrophysics that presents a fully comprehensive review of the subject. Utilizing the latest research, Gamma-ray Bursts is an essential desktop companion for graduate students and researchers in astrophysics.

  10. Improved limits on sterile neutrino dark matter using full-sky Fermi Gamma-ray Burst Monitor data

    NARCIS (Netherlands)

    Ng, K.C.Y.; Horiuchi, S.; Gaskins, J.M.; Smith, M.; Preece, R.

    2015-01-01

    A sterile neutrino of similar to keV mass is a well-motivated dark matter candidate. Its decay generates an x-ray line that offers a unique target for x-ray telescopes. For the first time, we use the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-Ray Space Telescope to search for sterile

  11. Sky alert! when satellites fail

    CERN Document Server

    Johnson, Les

    2013-01-01

    How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at areas where the loss could have catastrophic effects. The book - demonstrates our dependence on space technology and satellites; - outlines the effect on our economy, defense, and daily lives if satellites and orbiting spacecraft were destroyed; - illustrates the danger of dead satellites, spent rocket stages, and space debris colliding with a functioning satellites; - demonstrates the threat of dramatically increased radiation levels associated with geomagnetic storms; - introduces space as a potential area of conflict between nations.

  12. Static Analysis Alert Audits: Lexicon and Rules

    Science.gov (United States)

    2016-11-04

    values. • Unless they have a strong guarantee to the contrary Example from recent history : Java Deserialization • Suppose an alert is raised for a...some initial feedback from two collaborators, who used our rules to audit several hundred alerts from C and Java codebases 32 Audit Rules and Lexicon

  13. Cosmic ray effect on the X-ray Trigger Telescope of UFFO/Lomonosov using YSO scintillation crystal array in space

    DEFF Research Database (Denmark)

    Kim, M. B.; Jeong, S.; Jeong, H. M.

    2017-01-01

    UFFO Burst Alert and Trigger telescope (UBAT) is the X-ray trigger telescope of UFFO/Lomonosov to localize X-ray source with coded mask method and X-ray detector. Its X-ray detector is made up of 36 8×8 pixels Yttrium OxyorthoSilicate (Y2SiO5:Ce, YSO) scintillation crystal arrays and 36 64-channel...... Multi-Anode PhotoMultiplier Tubes (MAPMTs) for space mission. Its effective detection area is 161cm2 and energy range is several keV to 150 keV. It was successfully launched in April 28, 2016. In several calibration run, we got several X-ray background data. We already knew X-ray background flux is 2......-3 counts/cm2/sec in space. However our X-ray background data shows approximately 7-8 times higher than what we know. There are many candidates to explain high X-ray background count in space. One of candidates is cosmic ray. We will report cosmic ray effect on the X-ray detector using YSO scintillation...

  14. Implementation and Operation of a Robotic Telescope on Skynet

    Science.gov (United States)

    Smith, Adam B.; Caton, Daniel B.; Hawkins, R. Lee

    2016-05-01

    We describe the implementation of a remotely operated telescope on the Skynet Robotic Telescope Network, a system developed and run by the University of North Carolina-Chapel Hill. Our telescope, operated by Appalachian State University at its Dark Sky Observatory, runs robotically on this queue-scheduled system, automatically taking calibration images and acquiring program images, and responding to Internet commands to image the afterglow of accessible Gamma-Ray Burst events. We describe the process of implementing a Skynet-run telescope from our client-side view, and offer advice for others who might consider putting telescopes on Skynet. The implementation has proven very successful, obtaining over a hundred thousand images over the past six years, of various targets for research and educational purposes, and has responded to several GRB observation requests with several afterglow detections.

  15. Rapid optical variability of the gamma-ray burst grb 080319b and its central engine

    Science.gov (United States)

    Beskin, G.; Karpov, S.; Bondar, S.; Guarnieri, A.; Bartolini, C.; Greco, D.; Piccioni, A.

    2010-07-01

    The results of observations of the optical emission that accompanied the gamma-ray burst GRB 080319B are reported. Observations were made using the TORTORA fast wide-field camera mounted on the REM robotic telescope in Chile. The behavior of the light curve before, during, and after the gamma-ray burst is described. The light curve consists of four, possibly periodic, 5-7 s long peaks 8-9 s apart. The behavior of the burst in the gamma and optical energy ranges are compared and the results of the theoretical interpretation of this comparison are reported.

  16. Fine and Superfine Structure of the Decameter-Hectometer Type II Burst on 7 June 2011

    Science.gov (United States)

    Dorovskyy, V. V.; Melnik, V. N.; Konovalenko, A. A.; Brazhenko, A. I.; Panchenko, M.; Poedts, S.; Mykhaylov, V. A.

    2015-07-01

    The characteristics of a type II burst with a herringbone structure observed both with ground-based radio telescopes (UTR-2 and URAN-2) and space-borne spectrometers (STEREO-A and B) are discussed. The burst was recorded on 7 June 2011 in the frequency band 3 - 33 MHz. It was characterized by extremely rich fine structure. Statistical analysis of more than 300 herringbone sub-bursts constituting the burst was performed separately for the positively (reverse) and negatively (forward) drifting sub-bursts. The sense and the degree of circular polarization of the herringbone sub-bursts were measured in a wide frequency band (16 - 32 MHz). A second-order fine frequency structure of the herringbone sub-bursts was observed and studied for the first time. Using STEREO/COR1 and SOHO/LASCO-C2 images, we determined the direction and radial speed of the coronal mass ejection responsible for the studied type II burst. The possible location of the type II burst source on the flank of the shock was found.

  17. Optothermally actuated capillary burst valve

    Science.gov (United States)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

    2017-04-01

    We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

  18. Introduction to Optical Burst Switching

    OpenAIRE

    KERNÁCS János; Szilágyi, Szabolcs

    2010-01-01

    Optical Burst Switching (OBS) isconsidered a popular switching paradigm for therealization of all-optical networks due to the balance itoffers between the coarse-grained Optical CircuitSwitching (OSC) and fine-grained Optical PacketSwitching (OPS). Given that the data are switched allopticallyat the burst level, Optical Burst Switchingcombines the transparency of Optical CircuitSwitching with the benefits of statistical multiplexingin Optical Packet Switching.

  19. Gamma-ray bursts.

    Science.gov (United States)

    Gehrels, Neil; Mészáros, Péter

    2012-08-24

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.

  20. 47 CFR 10.300 - Alert aggregator. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.300 Alert aggregator. ...

  1. Evaluation of Visual Alerts in the Maritime Domain

    National Research Council Canada - National Science Library

    Roberts, Shelley; Foster-Hunt, Tara

    2008-01-01

    .... As the auditory modality is overloaded in the current alerting system, one method of potentially reducing perceptual overload is to replace auditory alerts with alerts presented in the visual domain...

  2. Towards a wide area alerting and notification system

    CSIR Research Space (South Africa)

    McFerren, G

    2012-01-01

    Full Text Available This paper describes the concept of a Wide Area Alerting System (WAAS), a flexible ICT platform for building alerting and notification applications. It is tailored to the generation and dissemination of complex alerts or notifications derived from...

  3. 47 CFR 10.310 - Federal alert gateway. [Reserved

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Federal alert gateway. 10.310 Section 10.310 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.310 Federal alert gateway. ...

  4. NEW BURST ASSEMBLY AND SCHEDULING TECHNIQUE FOR OPTICAL BURST SWITCHING NETWORKS

    OpenAIRE

    Kavitha, V.; V.Palanisamy

    2013-01-01

    The Optical Burst Switching is a new switching technology that efficiently utilizes the bandwidth in the optical layer. The key areas to be concentrated in Optical Burst Switching (OBS) networks are the burst assembly and burst scheduling i.e., assignment of wavelengths to the incoming bursts. This study presents a New Burst Assembly and Scheduling (NBAS) technique in a simultaneous multipath transmission for burst loss recovery in OBS networks. A Redundant Burst Segmentation (RBS) is used fo...

  5. Short duration gamma ray bursts

    Indian Academy of Sciences (India)

    Abstract. After a short review of gamma ray bursts (GRBs), we discuss the physical implications of strong statistical correlations seen among some of the parameters of short duration bursts (90 < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.

  6. Short duration gamma ray bursts

    Indian Academy of Sciences (India)

    Gamma ray bursts (GRBs) are transient extragalactic events appearing randomly in the sky as localized flashes of electromagnetic radiation, consisting predominantly of photons with energy in the range of ~0.1–1 MeV. These sporadic bursts, occurring at the rate of ~600 per year, are isotropically distributed in the sky, ...

  7. ATST telescope mount: telescope of machine tool

    Science.gov (United States)

    Jeffers, Paul; Stolz, Günter; Bonomi, Giovanni; Dreyer, Oliver; Kärcher, Hans

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world, and will be able to provide the sharpest views ever taken of the solar surface. The telescope has a 4m aperture primary mirror, however due to the off axis nature of the optical layout, the telescope mount has proportions similar to an 8 meter class telescope. The technology normally used in this class of telescope is well understood in the telescope community and has been successfully implemented in numerous projects. The world of large machine tools has developed in a separate realm with similar levels of performance requirement but different boundary conditions. In addition the competitive nature of private industry has encouraged development and usage of more cost effective solutions both in initial capital cost and thru-life operating cost. Telescope mounts move relatively slowly with requirements for high stability under external environmental influences such as wind buffeting. Large machine tools operate under high speed requirements coupled with high application of force through the machine but with little or no external environmental influences. The benefits of these parallel development paths and the ATST system requirements are being combined in the ATST Telescope Mount Assembly (TMA). The process of balancing the system requirements with new technologies is based on the experience of the ATST project team, Ingersoll Machine Tools who are the main contractor for the TMA and MT Mechatronics who are their design subcontractors. This paper highlights a number of these proven technologies from the commercially driven machine tool world that are being introduced to the TMA design. Also the challenges of integrating and ensuring that the differences in application requirements are accounted for in the design are discussed.

  8. Reducing prescribing errors through creatinine clearance alert redesign.

    Science.gov (United States)

    Melton, Brittany L; Zillich, Alan J; Russell, Scott A; Weiner, Michael; McManus, M Sue; Spina, Jeffrey R; Russ, Alissa L

    2015-10-01

    Literature has shown that computerized creatinine clearance alerts reduce errors during prescribing, and applying human factors principles may further reduce errors. Our objective was to apply human factors principles to creatinine clearance alert design and assess whether the redesigned alerts increase usability and reduce prescribing errors compared with the original alerts. Twenty Veterans Affairs (VA) outpatient providers (14 physicians, 2 nurse practitioners, and 4 clinical pharmacists) completed 2 usability sessions in a counterbalanced study to evaluate original and redesigned alerts. Each session consisted of fictional patient scenarios with 3 medications that warranted prescribing changes because of renal impairment, each associated with creatinine clearance alerts. Quantitative and qualitative data were collected to assess alert usability and the occurrence of prescribing errors. There were 43% fewer prescribing errors with the redesigned alerts compared with the original alerts (P = .001). Compared with the original alerts, redesigned alerts significantly reduced prescribing errors for allopurinol and ibuprofen (85% vs 40% and 65% vs 25%, P = .012 and P = .008, respectively), but not for spironolactone (85% vs 65%). Nine providers (45%) voiced confusion about why the alert was appearing when they encountered the original alert design. When laboratory links were presented on the redesigned alert, laboratory information was accessed 3.5 times more frequently. Although prescribing errors were high with both alert designs, the redesigned alerts significantly improved prescribing outcomes. This investigation provides some of the first evidence on how alerts may be designed to support safer prescribing for patients with renal impairment. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Bursts de raios gama

    Science.gov (United States)

    Braga, J.

    2003-02-01

    Nos últimos anos, graças principalmente aos dados obtidos pelo Compton Gamma-Ray Observatory e pelo satélite ítalo-holandês BeppoSAX, grandes avanços foram obtidos no nosso conhecimento sobre os fascinantes e enigmáticos fenômenos conhecidos por "bursts"de raios gama. Neste trabalho é feita uma revisão sobre a fenomenologia desses misteriosos objetos e são apresentados os desenvolvimentos recentes nessa área palpitante da astrofísica moderna, ressaltando tanto os resultados observacionais obtidos até o momento quanto os modelos teóricos propostos para explixá-los.

  10. Alertness management : strategic naps in operational settings

    Science.gov (United States)

    1995-01-01

    Managing fatigue in complex operational settings requires attention to multiple factors, including hours of service, scheduling, education and training, countermeasures, technology, and research. Alertness-management strategies can be used to promote...

  11. Chemical Safety Alert: Safer Technology and Alternatives

    Science.gov (United States)

    This alert is intended to introduce safer technology concepts and general approaches, explains the concepts and principles, and gives brief examples of the integration of safer technologies into facility risk management activities.

  12. Solar radiation alert system : final report.

    Science.gov (United States)

    2009-03-01

    The Solar Radiation Alert (SRA) system continuously evaluates measurements of high-energy protons made by instruments on GOES satellites. If the measurements indicate a substantial elevation of effective dose rates at aircraft flight altitudes, the C...

  13. Alertness and visuospatial attention in clinical depression

    Directory of Open Access Journals (Sweden)

    Sturm Walter

    2011-05-01

    Full Text Available Abstract Background Cognitive deficits are a substantial burden in clinical depression. The present study considered dysfunction in the right-hemispheric attention network in depression, examining alertness and visuospatial attention. Methods Three computerized visuospatial attention tests and an alertness test were administered to 16 depressive patients and 16 matched healthy controls. Results Although no significant group effect was observed, alertness predicted reduced visuospatial performance in the left hemifield. Furthermore, sad mood showed a trend towards predicting left visual field omissions. Conclusions Decreased alertness may lead to lower left hemifield visuospatial attention; this mechanism may be responsible for a spatial bias to the right side in depression, even though treatment of depression and anxiety may reduce this cognitive deficit.

  14. Fire alerts on the geospatial semantic web

    CSIR Research Space (South Africa)

    Mcferren, GA

    2006-01-01

    Full Text Available conceptbased queries of data and knowledge repositories. Future AFIS versions would supply highly tuned, meaningful and customised fire alerts to users based on an open framework of geospatial Web services, ontologies and software agents. Other Webbased...

  15. Quantum key based burst confidentiality in optical burst switched networks.

    Science.gov (United States)

    Balamurugan, A M; Sivasubramanian, A

    2014-01-01

    The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

  16. Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks

    Directory of Open Access Journals (Sweden)

    A. M. Balamurugan

    2014-01-01

    Full Text Available The optical burst switching (OBS is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS. This paper deals with employing RC4 (stream cipher to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.

  17. Gérer et alerter

    Directory of Open Access Journals (Sweden)

    Valérie November

    2009-03-01

    Full Text Available Sur la base de deux événements d’inondation ayant touché récemment, dans des contextes politiques, organisationnels et hydrologiques bien différents, de nouveaux quartiers d’habitation, cet article rend compte des pratiques des acteurs impliqués dans des situations d’alerte et de crise en Suisse. Le recensement des acteurs – à travers leur rôle et leur place dans les mécanismes de préparation, d’alerte et de gestion –, ainsi que l’inventaire des documents mobilisés par ceux-ci, ont été réalisés dans les deux cas. Cette analyse a permis d’évaluer la gestion des événements, de déceler les changements organisationnels qui ont suivi les crises et de connaître la conception et le degré de formalisation du risque dont étaient dotés les différents acteurs avant et après les inondations. Plus encore, l’analyse a documenté les nouveaux processus d’alerte et de prévision qui ont été mis en place suite aux événements. Il s’avère ainsi que les épisodes d’inondation agissent de façon décisive sur la production de connaissances, à un degré variable selon les acteurs. Ces épisodes révèlent aussi parfois l’existence de connaissances « en attente » qui ne sont pas encore intégrées dans les procédures institutionnelles. Tant du point de vue de la prévision que de la gestion de la crise, ils permettent aussi de tester les canaux de l’information et de combler les déficits d’organisation, de collaboration et de sécurisation des dispositifs de communication. En outre, les risques et les crises liés aux inondations modifient les dynamiques et les politiques territoriales, conséquences du réajustement des réseaux d’acteurs. La mise en place de dispositifs d’intervention et de gestion de crise se montre cependant plus efficace que la refonte des dispositifs d’aménagement, généralement longue. Toutefois, la mémoire des événements se dégradant avec le temps, une inscription

  18. The microchannel x-ray telescope status

    Science.gov (United States)

    Götz, D.; Meuris, A.; Pinsard, F.; Doumayrou, E.; Tourrette, T.; Osborne, J. P.; Willingale, R.; Sykes, J. M.; Pearson, J. F.; Le Duigou, J. M.; Mercier, K.

    2016-07-01

    We present design status of the Microchannel X-ray Telescope, the focussing X-ray telescope on board the Sino- French SVOM mission dedicated to Gamma-Ray Bursts. Its optical design is based on square micro-pore optics (MPOs) in a Lobster-Eye configuration. The optics will be coupled to a low-noise pnCCD sensitive in the 0.2{10 keV energy range. With an expected point spread function of 4.5 arcmin (FWHM) and an estimated sensitivity adequate to detect all the afterglows of the SVOM GRBs, MXT will be able to provide error boxes smaller than 60 (90% c.l.) arc sec after five minutes of observation.

  19. Public Alerts for Hyper-Hazard Events

    Science.gov (United States)

    Woo, G.

    2011-12-01

    Hyper-hazard events pose an exceptional risk to threatened populations around the world. Because of the potentially grave number of casualties, special procedures need to be enacted to alert the public. This paper will consider the decision analysis associated with the provision of public alerts, and what training measures are required. Special focus will be on the issue of false alarms, and the social pyschology of population response to hazard warnings.

  20. Constraints on an Optical Afterglow and on Supernova Light Following the Short Burst GRB 050813

    NARCIS (Netherlands)

    Ferrero, P.; Sanchez, S.F.; Kann, D.A.; Klose, S.; Greiner, J.; Gorosabel, J.; Hartmann, D.H.; Henden, A.A.; Møller, P.; Palazzi, E.; Rau, A.; Stecklum, B.; Castro-Tirado, A.J.; Fynbo, J.P.U.; Hjorth, J.; Jakobsson, P.; Kouveliotou, C.; Masetti, N.; Pian, E.; Tanvir, N.R.; Wijers, R.A.M.J.

    2007-01-01

    We report early follow-up observations of the error box of the short burst GRB 050813 using the telescopes at Calar Alto and Observatorio Sierra Nevada, followed by deep VLT FORS2 I-band observations obtained under very good seeing conditions 5.7 and 11.7 days after the event. Neither a fading

  1. Diffuse emission of high-energy neutrinos from gamma-ray burst fireballs

    NARCIS (Netherlands)

    Tamborra, I.; Ando, S.

    2015-01-01

    Gamma-ray bursts (GRBs) have been suggested as possible sources of the high-energy neutrino flux recently detected by the IceCube telescope. We revisit the fireball emission model and elaborate an analytical prescription to estimate the high-energy neutrino prompt emission from pion and kaon decays,

  2. GRB 021004: Tomography of a gamma-ray burst progenitor and its host galaxy

    NARCIS (Netherlands)

    Castro-Tirado, A.J.; Møller, P.; García-Segura, G.; Gorosabel, J.; Pérez, E.; de Ugarte Postigo, A.; Solano, E.; Barrado, D.; Klose, S.; Kann, D.A.; Castro Cerón, J.M.; Kouveliotou, C.; Fynbo, J.P.U.; Hjorth, J.; Pedersen, H.; Pian, E.; Rol, E.; Palazzi, E.; Masetti, N.; Tanvir, N.R.; Vreeswijk, P.M.; Andersen, M.I.; Fruchter, A.S.; Greiner, J.; Wijers, R.A.M.J.; van den Heuvel, E.P.J.

    2010-01-01

    Aims. We analyse the distribution of matter around the progenitor star of gamma-ray burst GRB 021004 and the properties of its host galaxy with high-resolution echelle and near-infrared spectroscopy. Methods. Observations were taken by the 8.2 m Very Large Telescope with the Ultraviolet and Visual

  3. Accretion Disk Signatures in Type I X-Ray Bursts: Prospects for Future Missions

    Science.gov (United States)

    Keek, L.; Wolf, Z.; Ballantyne, D. R.

    2016-07-01

    Type I X-ray bursts and superbursts from accreting neutron stars illuminate the accretion disk and produce a reflection signal that evolves as the burst fades. Examining the evolution of reflection features in the spectra will provide insight into the burst-disk interaction, a potentially powerful probe of accretion disk physics. At present, reflection has been observed during only two bursts of exceptional duration. We investigate the detectability of reflection signatures with four of the latest well-studied X-ray observatory concepts: Hitomi, Neutron Star Interior Composition Explorer (NICER), Athena, and Large Observatory For X-ray Timing (LOFT). Burst spectra are modeled for different values for the flux, temperature, and the disk ionization parameter, which are representative for most known bursts and sources. The effective area and throughput of a Hitomi-like telescope are insufficient for characterizing burst reflection features. NICER and Athena will detect reflection signatures in Type I bursts with peak fluxes ≳10-7.5 erg cm-2 s-1 and also effectively constrain the reflection parameters for bright bursts with fluxes of ˜10-7 erg cm-2 s-1 in exposures of several seconds. Thus, these observatories will provide crucial new insight into the interaction of accretion flows and X-ray bursts. For sources with low line-of-sight absorption, the wide bandpass of these instruments allows for the detection of soft X-ray reflection features, which are sensitive to the disk metallicity and density. The large collecting area that is part of the LOFT design would revolutionize the field by tracing the evolution of the accretion geometry in detail throughout short bursts.

  4. Burst Oscillation Studies with NICER

    Science.gov (United States)

    Mahmoodifar, Simin; Strohmayer, Tod E.

    2017-08-01

    Type I X-ray bursts are thermonuclear flashes observed from the surfaces of accreting neutron stars in Low Mass X-ray Binaries. Oscillations have been observed during the rise and/or decay of some of these X-ray bursts. Those seen during the rise can be well explained by a spreading hot spot model, but large amplitude oscillations in the decay phase remain mysterious because of the absence of a clear-cut source of asymmetry. Here we present the results of our computations of the light curves and amplitudes of oscillations in X-ray burst models that realistically account for both flame spreading and subsequent cooling. For the cooling phase of the burst we use two simple phenomenological models. The first considers asymmetric cooling that can achieve high amplitudes in the tail. The second considers a sustained temperature pattern on the stellar surface that is produced by r-modes propagating in the surface fluid ocean of the star. We will present some simulated burst light curves/spectra using these models and NICER response files, and will show the capabilities of NICER to detect and study burst oscillations. NICER will enable us to study burst oscillations in the energy band below ~3 keV, where there has been no previous measurements of these phenomena.

  5. 77 FR 26701 - Review of the Emergency Alert System

    Science.gov (United States)

    2012-05-07

    ... Alerting Protocol, v. 1.2 USA Integrated Public Alert and Warning System Profile Version 1.0 (Oct. 13, 2009... COMMISSION 47 CFR Part 11 Review of the Emergency Alert System AGENCY: Federal Communications Commission... its rules governing the Emergency Alert System (EAS) rules so that EAS Participants may, but are not...

  6. 75 FR 4760 - Review of the Emergency Alert System

    Science.gov (United States)

    2010-01-29

    ... alert and warning system that exists primarily to enable the President of the United States to issue... Requirements; and a 2006 Public Alert and Warning System Executive Order. As a general matter, the Commission... Integrated Public Alert and Warnings System (IPAWS), envisioned as a network of alert systems utilizing...

  7. 76 FR 35810 - Review of the Emergency Alert System

    Science.gov (United States)

    2011-06-20

    ... Integrated Public Alert and Warning System for federal CAP-formatted messages; and (ii) state alert systems... Docket No. 04-296; FCC 11-82] Review of the Emergency Alert System AGENCY: Federal Communications... Commission (Commission) seeks comment on proposed changes to its rules governing the Emergency Alert System...

  8. 78 FR 16806 - The Commercial Mobile Alert System

    Science.gov (United States)

    2013-03-19

    ... downloaded at: www.fcc.gov . 1. The Warning Alert and Response Network Act (WARN Act) required the Commission... COMMISSION 47 CFR Part 10 The Commercial Mobile Alert System AGENCY: Federal Communications Commission... Commercial Mobile Alert System (CMAS) to Wireless Emergency Alerts (WEA). This is intended to conform the...

  9. 77 FR 16688 - Review of the Emergency Alert System

    Science.gov (United States)

    2012-03-22

    ... Integrated Public Alert and Warning System (IPAWS) technical standards and requirements for CAP and its... COMMISSION 47 CFR Part 11 Review of the Emergency Alert System AGENCY: Federal Communications Commission... its rules governing the Emergency Alert System (EAS) to codify the obligation to process alert...

  10. The Most Remote Gamma-Ray Burst

    Science.gov (United States)

    2000-10-01

    ESO Telescopes Observe "Lightning" in the Young Universe Summary Observations with telescopes at the ESO La Silla and Paranal observatories (Chile) have enabled an international team of astronomers [1] to measure the distance of a "gamma-ray burst", an extremely violent, cosmic explosion of still unknown physical origin. It turns out to be the most remote gamma-ray burst ever observed . The exceedingly powerful flash of light from this event was emitted when the Universe was very young, less than about 1,500 million years old, or only 10% of its present age. Travelling with the speed of light (300,000 km/sec) during 11,000 million years or more, the signal finally reached the Earth on January 31, 2000. The brightness of the exploding object was enormous, at least 1,000,000,000,000 times that of our Sun, or thousands of times that of the explosion of a single, heavy star (a "supernova"). The ESO Very Large Telescope (VLT) was also involved in trail-blazing observations of another gamma-ray burst in May 1999, cf. ESO PR 08/99. PR Photo 28a/00 : Sky field near GRB 000131 . PR Photo 28b/00 : The fading optical counterpart of GRB 000131 . PR Photo 28c/00 : VLT spectrum of GRB 000131 . What are Gamma-Ray Bursts? One of the currently most active fields of astrophysics is the study of the mysterious events known as "gamma-ray bursts" . They were first detected in the late 1960's by instruments on orbiting satellites. These short flashes of energetic gamma-rays last from less than a second to several minutes. Despite much effort, it is only within the last few years that it has become possible to locate the sites of some of these events (e.g. with the Beppo-Sax satellite ). Since the beginning of 1997, astronomers have identified about twenty optical sources in the sky that are associated with gamma-ray bursts. They have been found to be situated at extremely large (i.e., "cosmological") distances. This implies that the energy release during a gamma-ray burst within a few

  11. INTEGRAL and XMM-Newton observations of the weak gamma-ray burst GRB 030227

    DEFF Research Database (Denmark)

    Mereghetti, S.; Gotz, D.; Tiengo, A.

    2003-01-01

    We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led to the disco......We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led...... to the discovery of X-ray and optical afterglows. GRB 030227 had a duration of about 20 s and a peak flux of similar to1.1 photons cm(-2) s(-1) in the 20-200 keV energy range. The time-averaged spectrum can be fitted by a single power law with photon index similar to2, and we find some evidence for a hard......-to-soft spectral evolution. The X-ray afterglow has been detected starting only 8 hr after the prompt emission, with a 0.2-10 keV flux decreasing as t(-1) from 1.3 x 10(-12) to 5 x 10(-13) ergs cm(-2) s(-1). The afterglow spectrum is well described by a power law with photon index modified by a 1.94 +/- 0...

  12. 30 CFR 57.3461 - Rock bursts.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rock bursts. 57.3461 Section 57.3461 Mineral...-Underground Only § 57.3461 Rock bursts. (a) Operators of mines which have experienced a rock burst shall— (1) Within twenty four hours report to the nearest MSHA office each rock burst which: (i) Causes persons to...

  13. Magnetar-like X-Ray Bursts Suppress Pulsar Radio Emission

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, R. F.; Lyutikov, M.; Kaspi, V. M.; Tendulkar, S. P. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Burgay, M.; Possenti, A. [INAF–Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Esposito, P.; Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Israel, G. [INAF–Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Kerr, M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Sarkissian, J. [CSIRO Astronomy and Space Science, Parkes Observatory, P.O. Box 276, Parkes, NSW 2870 (Australia); Scholz, P., E-mail: archibald@astro.utoronto.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada)

    2017-11-10

    Rotation-powered pulsars and magnetars are two different observational manifestations of neutron stars: rotation-powered pulsars are rapidly spinning objects that are mostly observed as pulsating radio sources, while magnetars, neutron stars with the highest known magnetic fields, often emit short-duration X-ray bursts. Here, we report simultaneous observations of the high-magnetic-field radio pulsar PSR J1119−6127 at X-ray, with XMM-Newton and NuSTAR , and at radio energies with the Parkes radio telescope, during a period of magnetar-like bursts. The rotationally powered radio emission shuts off coincident with the occurrence of multiple X-ray bursts and recovers on a timescale of ∼70 s. These observations of related radio and X-ray phenomena further solidify the connection between radio pulsars and magnetars and suggest that the pair plasma produced in bursts can disrupt the acceleration mechanism of radio-emitting particles.

  14. On the three harmonics of solar type III bursts at the decameter wavelengths

    Science.gov (United States)

    Brazhenko, Anatolii; Pylaev, Oleg; Melnik, Valentin; Konovalenko, Alexandr; Zaqarashvili, Teimuraz; Rucker, Helmut; Frantsuzenko, Anatolii; Dorovskyy, Vladimir

    2014-05-01

    Harmonic structure of type III bursts are explained in terms of plasma emission mechanism. The second harmonic emission is well known. But there are theoretical papers about the third harmonic of type III bursts. And there were observations of the third harmonic of such types of bursts as U, J, V, II. We observed triple type III bursts where frequency ratio is close to 1:2:3. They are structures where type III emission is repeated at the double and triple frequencies. Incidentally, components of triple type III bursts are not only standard type III but also type IIIb bursts. We registered 30 triple bursts during 2011 and 2012 years. Observations were made by radio telescope URAN-2, Poltava, Ukraine. It enables polarization measurements at the frequencies 8 - 32 MHz. URAN-2 allows registration of radio emission with time and frequency resolution 10 ms and 4 kHz correspondingly. We analyze properties of the components of triple bursts and their dependencies on frequency, type of burst and on the position of the component within the triplet. The main properties of the components of triple bursts such as duration and drift rate are similar to those of standard type III and IIIb bursts. We find usual for type III bursts dependencies such as follow: duration decreases with frequency, the type IIIb bursts have always smaller duration at the same frequencies, all bursts drift from high to low frequencies. But we also find the linear dependence of drift rate on frequency. All components of a trio have the same sign of polarization. Polarization of the first component is always the highest in triple bursts. It corresponds to the generally accepted viewpoint about the first harmonic emission. The second and the third components of trio have low polarization. It is typical for the second and the third harmonics according to the plasma radiation mechanism. We discuss possible emission mechanisms and theoretical aspects of observed dependencies. The most of detected regularities

  15. Effects of workload, work complexity, and repeated alerts on alert fatigue in a clinical decision support system.

    Science.gov (United States)

    Ancker, Jessica S; Edwards, Alison; Nosal, Sarah; Hauser, Diane; Mauer, Elizabeth; Kaushal, Rainu

    2017-04-10

    Although alert fatigue is blamed for high override rates in contemporary clinical decision support systems, the concept of alert fatigue is poorly defined. We tested hypotheses arising from two possible alert fatigue mechanisms: (A) cognitive overload associated with amount of work, complexity of work, and effort distinguishing informative from uninformative alerts, and (B) desensitization from repeated exposure to the same alert over time. Retrospective cohort study using electronic health record data (both drug alerts and clinical practice reminders) from January 2010 through June 2013 from 112 ambulatory primary care clinicians. The cognitive overload hypotheses were that alert acceptance would be lower with higher workload (number of encounters, number of patients), higher work complexity (patient comorbidity, alerts per encounter), and more alerts low in informational value (repeated alerts for the same patient in the same year). The desensitization hypothesis was that, for newly deployed alerts, acceptance rates would decline after an initial peak. On average, one-quarter of drug alerts received by a primary care clinician, and one-third of clinical reminders, were repeats for the same patient within the same year. Alert acceptance was associated with work complexity and repeated alerts, but not with the amount of work. Likelihood of reminder acceptance dropped by 30% for each additional reminder received per encounter, and by 10% for each five percentage point increase in proportion of repeated reminders. The newly deployed reminders did not show a pattern of declining response rates over time, which would have been consistent with desensitization. Interestingly, nurse practitioners were 4 times as likely to accept drug alerts as physicians. Clinicians became less likely to accept alerts as they received more of them, particularly more repeated alerts. There was no evidence of an effect of workload per se, or of desensitization over time for a newly deployed

  16. LOCALIZATION OF GAMMA-RAY BURSTS USING THE FERMI GAMMA-RAY BURST MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Connaughton, V.; Briggs, M. S.; Burgess, J. M. [CSPAR and Physics Department, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Goldstein, A.; Wilson-Hodge, C. A. [Astrophysics Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Meegan, C. A.; Jenke, P.; Pelassa, V.; Xiong, S.; Bhat, P. N. [CSPAR, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Paciesas, W. S. [Universities Space Research Association, Huntsville, AL (United States); Preece, R. D. [Department of Space Science, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Gibby, M. H. [Jacobs Technology, Inc., Huntsville, AL (United States); Greiner, J.; Yu, H.-F. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Gruber, D. [Planetarium Südtirol, Gummer 5, I-39053 Karneid (Italy); Kippen, R. M. [Los Alamos National Laboratory, NM 87545 (United States); Byrne, D.; Fitzpatrick, G.; Foley, S., E-mail: valerie@nasa.gov [School of Physics, University College Dublin, Belfield, Stillorgan Road, Dublin 4 (Ireland); and others

    2015-02-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network, to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1°, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.°7 Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14°. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y axis better localized than those on the X axis.

  17. Localization of Gamma-Ray Bursts Using the Fermi Gamma-Ray Burst Monitor

    Science.gov (United States)

    Connaughton, V.; Briggs, M. S.; Goldstein, A.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Wilson-Hodge, C. A.; Gibby, M. H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R. M.; Pelassa, V.; Xiong, S.; Yu, H.-F.; Bhat, P. N.; Burgess, J. M.; Byrne, D.; Fitzpatrick, G.; Foley, S.; Giles, M. M.; Guiriec, S.; van der Horst, A. J.; von Kienlin, A.; McBreen, S.; McGlynn, S.; Tierney, D.; Zhang, B.-B.

    2015-02-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network, to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1°, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.°7 Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14°. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y axis better localized than those on the X axis.

  18. Early Time Optical Emission from Gamma-Ray Bursts

    Science.gov (United States)

    Kopac, D.; Gomboc, A.; Japelj, J.

    We present the study of a sample of Gamma-Ray Bursts (GRBs) with contemporaneous early time optical and gamma-ray detections. By performing detailed temporal and spectral analysis of 18 GRBs which show optical peaks during prompt gamma-ray emission, we find that in most cases early time optical emission shows sharp and steep behavior, with a rich diversity of GRBs' broadband spectral properties. These observational results, supported by a simple internal shock dissipation model, show that the standard external shock interpretation for early time optical emission is disfavored in most cases where early time optical peaks are sharp (Delta t/t robotic optical telescopes.

  19. Prioritizing earthquake and tsunami alerting efforts

    Science.gov (United States)

    Allen, R. M.; Allen, S.; Aranha, M. A.; Chung, A. I.; Hellweg, M.; Henson, I. H.; Melgar, D.; Neuhauser, D. S.; Nof, R. N.; Strauss, J. A.

    2015-12-01

    The timeline of hazards associated with earthquakes ranges from seconds for the strong shaking at the epicenter, to minutes for strong shaking at more distant locations in big quakes, to tens of minutes for a local tsunami. Earthquake and tsunami warning systems must therefore include very fast initial alerts, while also taking advantage of available time in bigger and tsunami-generating quakes. At the UC Berkeley Seismological Laboratory we are developing a suite of algorithms to provide the fullest possible information about earthquake shaking and tsunami inundation from seconds to minutes after a quake. The E-larmS algorithm uses the P-wave to rapidly detect an earthquake and issue a warning. It is currently issuing alerts to test users in as little as 3 sec after the origin time. Development of a new waveform detector may lead to even faster alerts. G-larmS uses permanent deformation estimates from GNSS stations to estimate the geometry and extent of rupture underway providing more accurate ground shaking estimates in big (M>~7) earthquakes. It performed well in the M6.0 2014 Napa earthquake. T-larmS is a new algorithm designed to extend alert capabilities to tsunami inundation. Rapid estimates of source characteristics for subduction zones event can not only be used to warn of the shaking hazard, but also the local tsunami inundation hazard. These algorithms are being developed, implemented and tested with a focus on the western US, but are also now being tested in other parts of the world including Israel, Turkey, Korea and Chile. Beta users in the Bay Area are receiving the alerts and beginning to implement automated actions. They also provide feedback on users needs, which has led to the development of the MyEEW smartphone app. This app allows beta users to receive the alerts on their cell phones. All these efforts feed into our ongoing assessment of directions and priorities for future development and implementation efforts.

  20. Gamma ray bursts, supernovae and metallicity in the intergalactic medium

    CERN Document Server

    Dado, S; De Rújula, Alvaro; Dado, Shlomo; Dar, Arnon

    2007-01-01

    The mean iron abundance observed in the intracluster medium of galaxy clusters is consistent with the mean amount of iron injected in the universe per unit volume by standard supernova (SN) explosions with a rate proportional to the cosmic star-formation rate. But very little is known about field SNe at high red-shifts. Such SNe could have occurred primarily in highly obscured environments, avoiding detection. Supporting evidence for field SNe is provided by SNe associated with gamma ray bursts (GRBs) without a host galaxy and by the ratio of well localized GRBs with and without a host galaxy. A direct test of the field-SN origin of iron in the intergalactic medium would require the measurement of their rate per comoving unit volume as function of red-shift. This is feasible with IR telescopes, such as the Spitzer Space Telescope.

  1. A Bubble Bursts

    Science.gov (United States)

    2005-01-01

    RCW 79 is seen in the southern Milky Way, 17,200 light-years from Earth in the constellation Centaurus. The bubble is 70-light years in diameter, and probably took about one million years to form from the radiation and winds of hot young stars. The balloon of gas and dust is an example of stimulated star formation. Such stars are born when the hot bubble expands into the interstellar gas and dust around it. RCW 79 has spawned at least two groups of new stars along the edge of the large bubble. Some are visible inside the small bubble in the lower left corner. Another group of baby stars appears near the opening at the top. NASA's Spitzer Space Telescope easily detects infrared light from the dust particles in RCW 79. The young stars within RCW 79 radiate ultraviolet light that excites molecules of dust within the bubble. This causes the dust grains to emit infrared light that is detected by Spitzer and seen here as the extended red features.

  2. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.

    2011-01-01

    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several

  3. Japanese radio telescopes

    Science.gov (United States)

    Kawaguchi, Noriyuki

    Japanese principal radio telescopes available for Very Long Baseline Interferometry (VLBI) observations are overviewed, and their characteristics and performances are summarized. Three fixed stations, Usuda, Nobeyama, and Kashima, and one 5-m mobile station use a hydrogen master-frequency standard, while other stations use an ultrastable X'tal oscillator locked to a cesium frequency standard. The 64-m telescope in Usuda developed for tracking satellites of deep-space missions is outlined, as well as the Kashima 34-m telescope covering a frequency range from 300 MHz to 49 GHz with 11 receivers. Attention is given to the Nobeyama 45-m telescope as a major telescope in Japan working in an international mm-VLBI network.

  4. Observing the Sun with Coronado telescopes telescopes

    CERN Document Server

    Pugh, Philip

    2007-01-01

    The Sun provides amateur astronomers with one of the few opportunities for daytime astronomy. In order to see the major features of our nearest star, special telescopes that have a very narrow visible bandwidth are essential. The bandwidth has to be as narrow as 1 A- 10-10 m (1 Angstrom) and centred on the absorption line of neutral hydrogen. This makes many major features of the Suna (TM)s chromosphere visible to the observer. Such narrow-band "Fabry-Perot etalon filters" are high technology, and until the introduction of the Coronado range of solar telescopes, were too expensive for amateur use. The entry-level Coronado telescope, the PST (Personal Solar Telescope) costs under 500. Solar prominences (vast columns of plasma, best seen at the edge of the solar disk), filaments, flares, sunspots, plage and active regions are all visible and can be imaged to produce spectacular solar photographs. Philip Pugh has assembled a team of contributors who show just how much solar work can be done with Coronado telesco...

  5. Fast Radio Burst Discovered in the Arecibo Pulsar ALFA Survey

    Science.gov (United States)

    Spitler, L. G.; Cordes, J. M.; Hessels, J. W. T.; Lorimer, D. R.; McLaughlin, M. A.; Chatterjee, S.; Crawford, F.; Deneva, J. S.; Kaspi, V. M.; Wharton, R. S.; Allen, B.; Bogdanov, S.; Brazier, A.; Camilo, F.; Freire, P. C. C.; Jenet, F. A.; Karako-Argaman, C.; Knispel, B.; Lazarus, P.; Lee, K. J.; van Leeuwen, J.; Lynch, R.; Ransom, S. M.; Scholz, P.; Siemens, X.; Stairs, I. H.; Stovall, K.; Swiggum, J. K.; Venkataraman, A.; Zhu, W. W.; Aulbert, C.; Fehrmann, H.

    2014-08-01

    Recent work has exploited pulsar survey data to identify temporally isolated, millisecond-duration radio bursts with large dispersion measures (DMs). These bursts have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; they may also be linked to new source classes. Until now, however, all so-called fast radio bursts (FRBs) have been detected with the Parkes radio telescope and its 13-beam receiver, casting some concern about the astrophysical nature of these signals. Here we present FRB 121102, the first FRB discovery from a geographic location other than Parkes. FRB 121102 was found in the Galactic anti-center region in the 1.4 GHz Pulsar Arecibo L-band Feed Array (ALFA) survey with the Arecibo Observatory with a DM = 557.4 ± 2.0 pc cm-3, pulse width of 3.0 ± 0.5 ms, and no evidence of interstellar scattering. The observed delay of the signal arrival time with frequency agrees precisely with the expectation of dispersion through an ionized medium. Despite its low Galactic latitude (b = -0.°2), the burst has three times the maximum Galactic DM expected along this particular line of sight, suggesting an extragalactic origin. A peculiar aspect of the signal is an inverted spectrum; we interpret this as a consequence of being detected in a sidelobe of the ALFA receiver. FRB 121102's brightness, duration, and the inferred event rate are all consistent with the properties of the previously detected Parkes bursts.

  6. Heterogeneity in Short Gamma-Ray Bursts

    Science.gov (United States)

    Norris, Jay P.; Gehrels Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample comprises 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales - durations, pulse structure widths, and peak intervals - for EE bursts are factors of approx 2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts - the anti-correlation of pulse intensity and width - continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/XRT. The median flux of the initial XRT detections for EE bursts (approx 6 X 10(exp -10) erg / sq cm/ s) is approx > 20 x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (approx 60,000 s) is approx 30 x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into more dense environments than non-EE bursts, or that the sometimes-dominant EE component efficiently p()wers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  7. Status of the large-size telescope prototyping for the Cherenkov Telescope Array

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Excellence Cluster ' ' Universe' ' , Technische Universitaet Muenchen, 85747 Garching b. Muenchen (Germany); Teshima, Masahiro [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Institute for Cosmic Ray Research, University of Tokyo (Japan); Schweizer, Thomas; Mirzoyan, Razmik; Wetteskind, Holger; Jablonski, Christopher; Reimann, Olaf [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Lorenz, Eckart [ETH Zuerich, CH-8093 Zuerich (Switzerland); Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany)

    2011-07-01

    The Cherenkov Telescope Array (CTA) observatory aims at increasing the sensitivity of ground-based gamma-ray (GeV/TeV energies) observatories by a factor >10 compared to current facilities, to extend the accessible gamma-ray energies from a few tens of GeV to a hundred TeV, and to improve on other parameters like the energy and angular resolution. Sensitivity at the lowest possible energies is important for a variety of key physics goals, like the observation of distant active galactic nuclei or gamma-ray bursts, but also for measuring pulsar cutoffs. For this aim, CTA will incorporate a number of central large-size telescopes (LSTs of 23 m diameter). In this presentation, design considerations and the status of the LST prototyping are reported.

  8. Self-Regulation: Calm, Alert, and Learning

    Science.gov (United States)

    Shanker, Stuart

    2010-01-01

    There is a growing awareness among developmental scientists that the better a child can self-regulate, the better she can rise to the challenge of mastering ever more complex skills and concepts. In the simplest terms, self-regulation can be defined as the ability to stay calmly focused and alert, which often involves--but cannot be reduced…

  9. Alerting or Somnogenic Light: Pick Your Color.

    Science.gov (United States)

    Bourgin, Patrice; Hubbard, Jeffrey

    2016-08-01

    In mammals, light exerts pervasive effects on physiology and behavior in two ways: indirectly through clock synchronization and the phase adjustment of circadian rhythms, and directly through the promotion of alertness and sleep, respectively, in diurnal and nocturnal species. A recent report by Pilorz and colleagues describes an even more complex role for the acute effects of light. In mice, blue light acutely causes behavioral arousal, whereas green wavelengths promote sleep. These opposing effects are mediated by melanopsin-based phototransduction through different neural pathways. These findings reconcile nocturnal and diurnal species through a common alerting response to blue light. One can hypothesize that the opposite responses to natural polychromatic light in night- or day-active animals may reflect higher sensitivity of nocturnal species to green, and diurnals to blue wavelengths, resulting in hypnogenic and alerting effects, respectively. Additional questions remain to be clarified. How do different light wavelengths affect other behaviors such as mood and cognition? How do those results apply to humans? How does light pose either a risk or benefit, depending on whether one needs to be asleep or alert? Indeed, in addition to timing, luminance levels, and light exposure duration, these findings stress the need to understand how best to adapt the color spectrum of light to our needs and to take this into account for the design of daily lighting concepts-a key challenge for today's society, especially with the emergence of LED light technology.

  10. Global Trade Alert | IDRC - International Development Research ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Global Trade Alert. As many economies witness the sharpest fall in exports in decades, and with unemployment rising to levels not seen since the 1980s, governments might be tempted to resort to protectionist policies. Although the world has not seen a return to the trade-distorting reactions of the 1930s, governments have ...

  11. CEI-PEA Alert, Summer 2006

    Science.gov (United States)

    Center for Educational Innovation - Public Education Association, 2006

    2006-01-01

    The "CEI-PEA Alert" is an advocacy newsletter that deals with topics of interest to all concerned with the New York City public schools. This issue includes: (1) Practical Skills & High Academic Standards: Career Technical Education; (2) Parents: Help Your Children Gain "Soft Skills" for the Workforce; (3) Culinary Arts…

  12. Alerts of forest disturbance from MODIS imagery

    Science.gov (United States)

    Hammer, Dan; Kraft, Robin; Wheeler, David

    2014-12-01

    This paper reports the methodology and computational strategy for a forest cover disturbance alerting system. Analytical techniques from time series econometrics are applied to imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to detect temporal instability in vegetation indices. The characteristics from each MODIS pixel's spectral history are extracted and compared against historical data on forest cover loss to develop a geographically localized classification rule that can be applied across the humid tropical biome. The final output is a probability of forest disturbance for each 500 m pixel that is updated every 16 days. The primary objective is to provide high-confidence alerts of forest disturbance, while minimizing false positives. We find that the alerts serve this purpose exceedingly well in Pará, Brazil, with high probability alerts garnering a user accuracy of 98 percent over the training period and 93 percent after the training period (2000-2005) when compared against the PRODES deforestation data set, which is used to assess spatial accuracy. Implemented in Clojure and Java on the Hadoop distributed data processing platform, the algorithm is a fast, automated, and open source system for detecting forest disturbance. It is intended to be used in conjunction with higher-resolution imagery and data products that cannot be updated as quickly as MODIS-based data products. By highlighting hotspots of change, the algorithm and associated output can focus high-resolution data acquisition and aid in efforts to enforce local forest conservation efforts.

  13. Alertness maintaining tasks (AMTs) while driving.

    Science.gov (United States)

    Oron-Gilad, Tal; Ronen, Adi; Shinar, David

    2008-05-01

    We evaluated the effectiveness of alertness maintaining tasks (AMTs) on driver performance, subjective feelings, and psychophysiological state in monotonous simulated driving in two experiments. In the first experiment, 12 professional truck drivers participated in five sessions of simulated driving: driving only, driving with one of three AMTs (counterbalanced), and driving while listening to music. AMTs were not equally effective in maintaining alertness. The trivia AMT prevented driving performance deterioration, and increased alertness (measured by standardized HRV). The choice reaction time AMT was least demanding but also increased subjective sleepiness and reduced arousal (measured by alpha/beta ratio). The working memory AMT caused a significant decrement in driving speed, increased subjective fatigue, and was regarded by the participants as detrimental to driving. Trivia was preferred by the majority of the drivers over the other two AMTs. Experiment 2 further examined the utility of the trivia AMT. When the drivers engaged in the trivia AMT they maintained better driving performance and perceived the driving duration as shorter than the control condition. The two experiments demonstrated that AMTs can have a positive effect on alertness. The effect is localized in the sense that it does not persist beyond the period of the AMT activation.

  14. Alerting or Somnogenic Light: Pick Your Color.

    Directory of Open Access Journals (Sweden)

    Patrice Bourgin

    2016-08-01

    Full Text Available In mammals, light exerts pervasive effects on physiology and behavior in two ways: indirectly through clock synchronization and the phase adjustment of circadian rhythms, and directly through the promotion of alertness and sleep, respectively, in diurnal and nocturnal species. A recent report by Pilorz and colleagues describes an even more complex role for the acute effects of light. In mice, blue light acutely causes behavioral arousal, whereas green wavelengths promote sleep. These opposing effects are mediated by melanopsin-based phototransduction through different neural pathways. These findings reconcile nocturnal and diurnal species through a common alerting response to blue light. One can hypothesize that the opposite responses to natural polychromatic light in night- or day-active animals may reflect higher sensitivity of nocturnal species to green, and diurnals to blue wavelengths, resulting in hypnogenic and alerting effects, respectively. Additional questions remain to be clarified. How do different light wavelengths affect other behaviors such as mood and cognition? How do those results apply to humans? How does light pose either a risk or benefit, depending on whether one needs to be asleep or alert? Indeed, in addition to timing, luminance levels, and light exposure duration, these findings stress the need to understand how best to adapt the color spectrum of light to our needs and to take this into account for the design of daily lighting concepts-a key challenge for today's society, especially with the emergence of LED light technology.

  15. Funding Alert Subscribe Confirmation | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Thank you. Please check your email ( ) to confirm your subscription to the IDRC Funding Alerts. Please note: the link in your confirmation email is valid for 3 days, so please reply promptly. We fund researchers driving global change. Careers · Contact Us · Subscribe · Unsubscribe · Site map. Follow us; Facebook · Twitter ...

  16. Automated attendance management and alert system | Rahim ...

    African Journals Online (AJOL)

    “Automated Attendance Management and Alert System (AAMAS)” was developed to help UiTM lecturers and Academic Affairs Department in monitoring students' absenteeism and improving the absenteeism record management. AAMAS provides various functions, from managing and recording students' attendance record ...

  17. For Emergency Alerts, Some Colleges Try Sirens

    Science.gov (United States)

    Young, Jeffrey R.

    2008-01-01

    Colleges and universities, ever more mindful of campus safety, are installing outdoor sirens. The systems can blast spoken messages or tone alerts of danger--and one of the preset messages on many of the public-address systems warns: "There is a shooter on campus. Seek shelter immediately." As college officials reviewed their…

  18. IR panoramic alerting sensor concepts and applications

    Science.gov (United States)

    de Jong, Arie N.; Schwering, Piet B. W.

    2003-09-01

    During the last decade, protection of military and civilian operational platforms against weapons like guns, grenades, missiles, Unmanned Combat Aerial (and surface) Vehicles (UCAV's) and mines, has been an issue of increased importance due to the improved kill-probability of these threats. The standard countermeasure package of armour, guns, decoys, jammers, camouflage nets and smokes is inadequate when not accompanied by a suitable sensor package, primarily consisting of an alerting device, triggering consecutive steps in the countermeasure-chain. In this process of alert four different detection techniques are considered: pre-alert, giving the directions of possible attack, detection of an action of attack, identification of the threat and finally the precise localization (3-D). The design of the alerting device is greatly depending on the platform, on which it will be used, the associated and affordable cost and the nature of the threat. A number of sensor packages, considered, developed and evaluated at TNO-FEL is presented for simple, medium size and large and expensive platforms. In recent years the requirements for these sensors have become more and more strigent due to the growing number of scenarios. The attack can practically be from any direction, implying the need for a large Field of Regard (FOR), the attack range can vary considerably and the type of threat can be very diverse, implying great flexibility and dynamic range and rapid response of the sensor. Especially the localization at short ranges is a challenging issue. Various configurations including advantages and drawbacks are discussed.

  19. Strategies for Studying the Sources of Gamma Ray Bursts

    Science.gov (United States)

    Cline, T. L.; Norris, J. P.; Hurley, K. C.

    2003-01-01

    The study of gamma ray bursts (GRBs) has rapidly evolved in recent years with the discovery of their cosmological nature and with BATSE, BeppoSAX, HETE and the IPN enabling a wide variety of associated . afterglow measurements. Multiwavelength observations ranging through the radio, optical, soft and hard x-ray, and gamma-ray regimes have exploded the field of GRB interpretation. Also, the Amanda, Milagro and LIGO experiments can search for related neutrino, cosmic-ray photon, and gravitational radiation events, even with the delayed alerts, such as from the IPN. The infrared region, where the optical emissions from sources at the extreme distances may be shifted, will become important but is undersubscribed. The soon-to-be launched Swift mission will greatly broaden the GRB discipline, and a strategy for associated ground-based measurements is outlined. The need for the improved global distribution of all instruments, in particular, robotic infrared detectors, is cited.

  20. Gamma-ray bursts and their use as cosmic probes

    Science.gov (United States)

    Schady, Patricia

    2017-07-01

    Since the launch of the highly successful and ongoing Swift mission, the field of gamma-ray bursts (GRBs) has undergone a revolution. The arcsecond GRB localizations available within just a few minutes of the GRB alert has signified the continual sampling of the GRB evolution through the prompt to afterglow phases revealing unexpected flaring and plateau phases, the first detection of a kilonova coincident with a short GRB, and the identification of samples of low-luminosity, ultra-long and highly dust-extinguished GRBs. The increased numbers of GRB afterglows, GRB-supernova detections, redshifts and host galaxy associations has greatly improved our understanding of what produces and powers these immense, cosmological explosions. Nevertheless, more high-quality data often also reveal greater complexity. In this review, I summarize some of the milestones made in GRB research during the Swift era, and how previous widely accepted theoretical models have had to adapt to accommodate the new wealth of observational data.

  1. Gamma-ray bursts and their use as cosmic probes.

    Science.gov (United States)

    Schady, Patricia

    2017-07-01

    Since the launch of the highly successful and ongoing Swift mission, the field of gamma-ray bursts (GRBs) has undergone a revolution. The arcsecond GRB localizations available within just a few minutes of the GRB alert has signified the continual sampling of the GRB evolution through the prompt to afterglow phases revealing unexpected flaring and plateau phases, the first detection of a kilonova coincident with a short GRB, and the identification of samples of low-luminosity, ultra-long and highly dust-extinguished GRBs. The increased numbers of GRB afterglows, GRB-supernova detections, redshifts and host galaxy associations has greatly improved our understanding of what produces and powers these immense, cosmological explosions. Nevertheless, more high-quality data often also reveal greater complexity. In this review, I summarize some of the milestones made in GRB research during the Swift era, and how previous widely accepted theoretical models have had to adapt to accommodate the new wealth of observational data.

  2. Physicians' responses to computerized drug interaction alerts with password overrides.

    Science.gov (United States)

    Nasuhara, Yasuyuki; Sakushima, Ken; Endoh, Akira; Umeki, Reona; Oki, Hiromitsu; Yamada, Takehiro; Iseki, Ken; Ishikawa, Makoto

    2015-08-28

    Although evidence has suggested that computerized drug-drug interaction alert systems may reduce the occurrence of drug-drug interactions, the numerous reminders and alerts generated by such systems could represent an excessive burden for clinicians, resulting in a high override rate of not only unimportant, but also important alerts. We analyzed physicians' responses to alerts of relative contraindications and contraindications for coadministration in a computerized drug-drug interaction alert system at Hokkaido University Hospital. In this system, the physician must enter a password to override an alert and continue an order. All of the drug-drug interaction alerts generated between December 2011 and November 2012 at Hokkaido University Hospital were included in this study. The system generated a total of 170 alerts of relative contraindications and contraindication for coadministration; 59 (34.7 %) of the corresponding orders were cancelled after the alert was accepted, and 111 (65.3 %) were overridden. The most frequent contraindication alert was for the combination of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors and fibrates. No incidents involving drug-drug interactions were reported among patients who were prescribed contraindicated drug pairs after an override. Although computerized drug-drug interaction alert systems that require password overrides appear useful for promoting medication safety, having to enter passwords to override alerts may represent an excessive burden for the prescribing physician. Therefore, both patient safety and physicians' workloads should be taken into consideration in future designs of computerized drug-drug interaction alert systems.

  3. Gemini telescope structure design

    Science.gov (United States)

    Raybould, Keith; Gillett, Paul E.; Hatton, Peter; Pentland, Gordon; Sheehan, Mike; Warner, Mark

    1994-06-01

    The Gemini project is an international collaboration to design, fabricate, and assemble two 8 M telescopes, one on Mauna Kea in Hawaii, the other on Cerro Pachon in Chile. The telescopes will be national facilities designed to meet the Gemini Science Requirements (GSR), a document developed by the Gemini Science Committee (GSC) and the national project scientists. The Gemini telescope group, based on Tucson, has developed a telescope structure to meet the GSR. This paper describes the science requirements that have technically driven the design, and the features that have been incorporated to meet these requirements. This is followed by a brief description of the telescope design. Finally, analyses that have been performed and development programs that have been undertaken are described briefly. Only the designs that have been performed by the Gemini Telescope Structure, Building and Enclosure Group are presented here; control, optical systems, acquisition and guiding, active and adaptive optics, Cassegrain rotator and instrumentation issues are designed and managed by others and will not be discussed here, except for a brief description of the telescope configurations to aid subsequent discussions.

  4. CONNECTING THE GAMMA RAY BURST RATE AND THE COSMIC STAR FORMATION HISTORY: IMPLICATIONS FOR REIONIZATION AND GALAXY EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Brant E.; Ellis, Richard S., E-mail: brant@astro.caltech.edu [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2012-01-10

    The contemporary discoveries of galaxies and gamma ray bursts (GRBs) at high redshift have supplied the first direct information on star formation when the universe was only a few hundred million years old. The probable origin of long duration GRBs in the deaths of massive stars would link the universal GRB rate to the redshift-dependent star formation rate (SFR) density, although exactly how is currently unknown. As the most distant GRBs and star-forming galaxies probe the reionization epoch, the potential reward of understanding the redshift-dependent ratio {Psi}(z) of the GRB rate to SFR is significant and includes addressing fundamental questions such as incompleteness in rest-frame UV surveys for determining the SFR at high redshift and time variations in the stellar initial mass function. Using an extensive sample of 112 GRBs above a fixed luminosity limit drawn from the Second Swift Burst Alert Telescope catalog and accounting for uncertainty in their redshift distribution by considering the contribution of 'dark' GRBs, we compare the cumulative redshift distribution N(< z) of GRBs with the star formation density {rho}-dot{sub *}(z) measured from UV-selected galaxies over 0 < z <4. Strong evolution (e.g., {Psi}(z){proportional_to}(1 + z){sup 1.5}) is disfavored (Kolmogorov-Smirnov test P < 0.07). We show that more modest evolution (e.g., {Psi}(z){proportional_to}(1 + z){sup 0.5}) is consistent with the data (P Almost-Equal-To 0.9) and can be readily explained if GRBs occur primarily in low-metallicity galaxies which are proportionally more numerous at earlier times. If such trends continue beyond z {approx_equal} 4, we find that the discovery rate of distant GRBs implies an SFR density much higher than that inferred from UV-selected galaxies. While some previous studies of the GRB-SFR connection have concluded that GRB-inferred star formation at high redshift would be sufficient to maintain cosmic reionization over 6

  5. Bursts in intermittent aeolian saltation

    CERN Document Server

    Carneiro, M V; Herrmann, H J

    2014-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of intermittent flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the critical Shields number $\\theta_c$. The time delay between each burst decreases on average with the increase of the Shields number until saltation becomes non-intermittent and the sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain intermittent flux even below the threshold $\\theta_c$ for natural saltation initiation.

  6. Telescopic vision contact lens

    Science.gov (United States)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  7. Hubble Space Telescope

    Science.gov (United States)

    1990-01-01

    An overview of the mission of the Hubble Space Telescope, a joint project between NASA and the European Space Agency which will be used to study deep space, as well as our solar system is presented. The video contains animations depicting the Hubble Space Telescope in orbit, as well as footage of scientists at the Space Telescope Science Institute making real time observations. The images Hubble acquires will be downloaded into a database that contains images of over 19,000,000 celestial objects called the Star Catalog.

  8. Ritchey-Chretien Telescope

    Science.gov (United States)

    Rosin, S.; Amon, M. (Inventor)

    1973-01-01

    A Ritchey-Chretien telescope is described which was designed to respond to images located off the optical axis by using two transparent flat plates positioned in the ray path of the image. The flat plates have a tilt angle relative to the ray path to compensate for astigmatism introduced by the telescope. The tilt angle of the plates is directly proportional to the off axis angle of the image. The plates have opposite inclination angles relative to the ray paths. A detector which is responsive to the optical image as transmitted through the plates is positioned approximately on the sagittal focus of the telescope.

  9. Wireless Emergency Alerts (WEA) Cybersecurity Risk Management Strategy for Alert Originators

    Science.gov (United States)

    2014-03-01

    code that is intended to cause undesired effects, security breaches, or dam- age to a system (e.g., scripts, viruses , worms, Trojan horses , backdoors...latest version of software but is redirected to a malicious site that installs malware (e.g., a virus , Trojan , worm, or key logger...appropriate.  The alert originator should run virus scans on its AOS periodically. The alert originator should respond to viruses found on its systems as

  10. MedWatch Safety Alerts for Human Medical Products

    Data.gov (United States)

    U.S. Department of Health & Human Services — MedWatch alerts provide timely new safety information on human drugs, medical devices, vaccines and other biologics, dietary supplements, and cosmetics. The alerts...

  11. Searching for neutrino bursts in the galaxy: 36 years of exposure

    Science.gov (United States)

    Novoseltsev, Yu. F.; Boliev, M. M.; Volchenko, V. I.; Volchenko, G. V.; Dzaparova, I. M.; Kochkarov, M. M.; Novoseltseva, R. V.; Petkov, V. B.; Yanin, A. F.

    2017-07-01

    The Baksan Underground Scintillation Telescope has operated within the program of searching for neutrino bursts since the mid-1980s. We present the current status of the experiment and some results related to the investigation of background events and the stability of facility operation. Over the period from June 30, 1980, to December 31, 2016, the pure observation time was 31.27 years. No neutrino burst candidate event from the explosion of a core-collapse supernova in the Galaxy was recorded in this time. This sets an upper bound of 0.074 yr-1 on the mean frequency of gravitational stellar collapses in the Galaxy at a 90% confidence level.

  12. The First FERMI-LAT Gamma-Ray Burst Catalog

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; hide

    2013-01-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy great than (20 MeV) gamma-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above approximately 20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  13. THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Asano, K. [Interactive Research Center of Science, Tokyo Institute of Technology, Meguro City, Tokyo 152-8551 (Japan); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d' Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bechtol, K.; Bloom, E. D. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bhat, P. N. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Bissaldi, E. [Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck (Austria); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Bonnell, J.; Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bouvier, A., E-mail: nicola.omodei@stanford.edu, E-mail: giacomov@slac.stanford.edu [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); and others

    2013-11-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (∼> 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ∼20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  14. Gamma Ray Burst Optical Counterpart Search Experiment (GROCSE)

    Science.gov (United States)

    Park, H. S.; Ables, E.; Bionta, R. M.; Ott, L.; Parker, E.; Akerlof, C.; Lee, B.; Wallace, S.; Barthelmy, S.; Butterworth, P.

    1995-01-01

    GROCSE (Gamma-Ray Optical Counterpart Search Experiments) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE 1, is sensitive down to Mv (approximately) 8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach Mv (approximately) 14 with a 5 second exposure. GROCSE 2 consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2K x 2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6 x 17.6 (degree). GROCSE 2 will be operated by the end of 1995. In this paper, the authors present an overview of the GROCSE system and the results of measurements with a GROCSE 2 prototype unit.

  15. HOW ELSE CAN WE DETECT FAST RADIO BURSTS?

    Energy Technology Data Exchange (ETDEWEB)

    Lyutikov, Maxim [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States); Lorimer, Duncan R., E-mail: lyutikov@purdue.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315 (United States)

    2016-06-20

    We discuss possible electromagnetic signals accompanying Fast Radio Bursts (FRBs) that are expected in the scenario where FRBs originate in neutron star magnetospheres. For models involving Crab-like giant pulses, no appreciable contemporaneous emission is expected at other wavelengths. However, magnetar giant flares, driven by the reconfiguration of the magnetosphere, can produce both contemporaneous bursts at other wavelengths as well as afterglow-like emission. We conclude that the best chances are: (i) prompt short GRB-like emission, (ii) a contemporaneous optical flash that can reach naked eye peak luminosity (but only for a few milliseconds), and (iii) a high-energy afterglow emission. Case (i) could be tested by coordinated radio and high-energy experiments. Case (ii) could be seen in a coordinated radio-optical surveys, e.g., by the Palomar Transient Factory in a 60 s frame as a transient object of m = 15–20 mag with an expected optical detection rate of about 0.1 hr{sup −1}, an order of magnitude higher than in radio. Shallow, but large-area sky surveys such as ASAS-SN and EVRYSCOPE could also detect prompt optical flashes from the more powerful Lorimer-burst clones. The best constraints on the optical to radio power for this kind of emission could be provided by future observations with facilities like Large Synoptic Survey Telescope. Case (iii) might be seen in relatively rare cases that the relativistically ejected magnetic blob is moving along the line of sight.

  16. 78 FR 22270 - Special Fraud Alert: Physician-Owned Entities

    Science.gov (United States)

    2013-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Office of Inspector General Special Fraud Alert: Physician-Owned Entities AGENCY: Office... issued Special Fraud Alert on Physician-Owned Entities. Specifically, the Special Fraud Alert addressed...

  17. LISA Telescope Sensitivity Analysis

    Science.gov (United States)

    Waluschka, Eugene; Krebs, Carolyn (Technical Monitor)

    2002-01-01

    The Laser Interferometer Space Antenna (LISA) for the detection of Gravitational Waves is a very long baseline interferometer which will measure the changes in the distance of a five million kilometer arm to picometer accuracies. As with any optical system, even one with such very large separations between the transmitting and receiving, telescopes, a sensitivity analysis should be performed to see how, in this case, the far field phase varies when the telescope parameters change as a result of small temperature changes.

  18. Eclipse telescope design factors

    Science.gov (United States)

    Hull, Tony; Trauger, John T.; Macenka, Steven A.; Moody, Dwight; Olarte, Guillermo; Sepulveda, Cesar; Tsuha, Walter; Cohen, David

    2003-02-01

    Very high contrast imagery, required for exoplanet image acquisition, imposes significantly different criteria upon telescope architecture than do the requirements imposed upon most spaceborne telescopes. For the Eclipse Mission, the fundamental figure-of-merit is a stellar contrast, or brightness reduction ratio, reaching a factor of 10-9 or better at star-planet distances as close as the 4th Airy ring. Factors necessary to achieve such contrast ratios are both irrelevant and largely ignored in contemporary telescope design. Although contemporary telescoeps now meet Hubble Space Telescope performance at substantially lower mass and cost than HST, control of mid-spatial-frequency (MSF) errors, crucial to coronagraphy, has not been emphasized. Accordingly, roughness at MSF has advanced little since HST. Fortunately, HST primary mirror smoothness would nearly satisfy Eclipse requirements, although other aspects of HST are undesirable for stellar coronagraphy. Conversely, the narrow field required for Eclipse eases other drivers of traditional telescope design. A systematic approach to telescope definition, with primary and sub-tier figures-of-merit, will be discussed in the context of the Eclipse Mission.

  19. Simultaneous X-Ray, Gamma-Ray, and Radio Observations of the Repeating Fast Radio Burst FRB 121102

    Science.gov (United States)

    Scholz, P.; Bogdanov, S.; Hessels, J. W. T.; Lynch, R. S.; Spitler, L. G.; Bassa, C. G.; Bower, G. C.; Burke-Spolaor, S.; Butler, B. J.; Chatterjee, S.; Cordes, J. M.; Gourdji, K.; Kaspi, V. M.; Law, C. J.; Marcote, B.; McLaughlin, M. A.; Michilli, D.; Paragi, Z.; Ransom, S. M.; Seymour, A.; Tendulkar, S. P.; Wharton, R. S.

    2017-09-01

    We undertook coordinated campaigns with the Green Bank, Effelsberg, and Arecibo radio telescopes during Chandra X-ray Observatory and XMM-Newton observations of the repeating fast radio burst FRB 121102 to search for simultaneous radio and X-ray bursts. We find 12 radio bursts from FRB 121102 during 70 ks total of X-ray observations. We detect no X-ray photons at the times of radio bursts from FRB 121102 and further detect no X-ray bursts above the measured background at any time. We place a 5σ upper limit of 3 × 10‑11 erg cm‑2 on the 0.5–10 keV fluence for X-ray bursts at the time of radio bursts for durations < 700 ms, which corresponds to a burst energy of 4 × 1045 erg at the measured distance of FRB 121102. We also place limits on the 0.5–10 keV fluence of 5 × 10‑10 and 1 × 10‑9 erg cm‑2 for bursts emitted at any time during the XMM-Newton and Chandra observations, respectively, assuming a typical X-ray burst duration of 5 ms. We analyze data from the Fermi Gamma-ray Space Telescope Gamma-ray Burst Monitor and place a 5σ upper limit on the 10–100 keV fluence of 4 × 10‑9 erg cm‑2 (5 × 1047 erg at the distance of FRB 121102) for gamma-ray bursts at the time of radio bursts. We also present a deep search for a persistent X-ray source using all of the X-ray observations taken to date and place a 5σ upper limit on the 0.5–10 keV flux of 4 × 10‑15 erg s‑1 cm‑2 (3 × 1041 erg s‑1 at the distance of FRB 121102). We discuss these non-detections in the context of the host environment of FRB 121102 and of possible sources of fast radio bursts in general.

  20. Optothermally actuated capillary burst valve

    DEFF Research Database (Denmark)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders

    2017-01-01

    be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett...

  1. Respiratory burst oxidase of fertilization.

    Science.gov (United States)

    Heinecke, J W; Shapiro, B M

    1989-02-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation of egg activation modulate the activity of the oxidase. Inhibitors were used to test the relevance of this oxidase to the respiratory burst of fertilization. Procaine, two phenothiazines, and N-ethylmaleimide (but not iodoacetamide) inhibited H2O2 production by the oxidase fraction and oxygen consumption by activated eggs. The ATP requirement suggested that protein kinase activity might regulate the respiratory burst of fertilization; consonant with this hypothesis, H-7 and staurosporine were inhibitory. The respiratory burst oxidase of fertilization is an NADPH:O2 oxidoreductase that appears to be regulated by a protein kinase; although it bears a remarkable resemblance to the neutrophil oxidase, unlike the latter it does not form O2- as its initial product.

  2. FERMIGBRST - Fermi GBM Burst Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — This table lists all of the triggers observed by a subset of the 14 GBM detectors (12 NaI and 2 BGO) which have been classified as gamma-ray bursts (GRBs). Note that...

  3. The high energy telescope on EXIST

    Science.gov (United States)

    Hong, J.; Grindlay, J. E.; Allen, B.; Barthelmy, S. D.; Skinner, G. K.; Gehrels, N.

    2009-08-01

    The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed next generation multi-wavelength survey mission. The primary instrument is a High Energy telescope (HET) that conducts the deepest survey for Gamma-ray Bursts (GRBs), obscured-accreting and dormant Supermassive Black Holes and Transients of all varieties for immediate followup studies by the two secondary instruments: a Soft X-ray Imager (SXI) and an Optical/Infrared Telescope (IRT). EXIST will explore the early Universe using high redshift GRBs as cosmic probes and survey black holes on all scales. The HET is a coded aperture telescope employing a large array of imaging CZT detectors (4.5 m2, 0.6 mm pixel) and a hybrid Tungsten mask. We review the current HET concept which follows an intensive design revision by the HET imaging working group and the recent engineering studies in the Instrument and Mission Design Lab at the Goddard Space Flight Center. The HET will locate GRBs and transients quickly (<10-30 sec) and accurately (< 20") for rapid (< 1-3 min) onboard followup soft X-ray and optical/IR (0.3-2.2 μm) imaging and spectroscopy. The broad energy band (5-600 keV) and the wide field of view (~90° × 70&° at 10% coding fraction) are optimal for capturing GRBs, obscured AGNs and rare transients. The continuous scan of the entire sky every 3 hours will establish a finely-sampled long-term history of many X-ray sources, opening up new possibilities for variability studies.

  4. Observation of two coronal mass ejections on April 7, 2011 by radio telescope URAN-2

    Science.gov (United States)

    Brazhenko, A.; Melnik, V.; Konovalenko, A.; Dorovskyy, V.; Vashchishin, V.; Franzusenko, A.; Rucker, H.

    2012-09-01

    Two CME's (coronal mass ejection) were registered by SOHO and STEREO on April 7, 2011. The results of observations obtained by radio telescope URAN-2 of different CME manifestations in radio emission at decameter wavelengths are discussed in this paper. Particularly we report about registration of new type of fine structure of type II bursts.

  5. The High Energy Telescope on EXIST: Hunting High Red-shift GRBs and Other Exotic Transients

    Science.gov (United States)

    Hong, JaeSub; Grindlay, J.; Allen, B.; Skinner, G. K.; Finger, M. H.; Jernigan, J. G.; EXIST Team

    2009-01-01

    The current baseline design of the High Energy Telescope (HET) on EXIST will localize high red-shift Gamma-Ray Bursts (GRBs) and other exotic transients fast (EXIST design concept, we review the observing strategy to maximize the science return and report the latest development of the CZT detectors for HET.

  6. Detecting pipe bursts by monitoring water demand

    NARCIS (Netherlands)

    Bakker, M.; Vreeburg, J.H.G.; Van der Roer, M.; Sperber, V.

    2012-01-01

    An algorithm which compares measured and predicted water demands to detect pipe bursts was developed and tested on three data sets of water demand and reported pipe bursts of three years. The algorithm proved to be able to detect bursts where the water loss exceeds 30% of the average water demand in

  7. Wireless Emergency Alerts: New York City Demonstration

    Science.gov (United States)

    2013-06-01

    hour xx = minute ss = second zz:zz = time zone AVA Avalanche Watch CAE Child Abduction Emergency CEM Civil Emergency Message LAE Local Area...cost of the ef- fort to obtain authorization to use WEA, the cost of getting and using alert origination soft - ware, and the cost of training...inter- nal test will tell you whether your staff knows how to use your IPAWS-compatible soft - ware, that the software works as you expected it to

  8. Simultaneous NuSTAR/Chandra Observations of The Bursting Pulsar GRO J1744-28 During Its Third Reactivation

    DEFF Research Database (Denmark)

    Younes, G.; Kouveliotou, C.; Grefenstette, B. W.

    2015-01-01

    We report on a 10 ks simultaneous Chandra/High Energy Transmission Grating (HETG)-Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the Bursting Pulsar, GRO J1744-28, during its third detected outburst since discovery and after nearly 18 yr of quiescence. The source is detected up to 60...

  9. On the "canonical behaviour" of the X-ray afterglows of the Gamma Ray Bursts observed with Swift's XRT

    CERN Document Server

    Dado, S; De Rújula, Alvaro; Dado, Shlomo; Dar, Arnon

    2006-01-01

    The "canonical behaviour" of the early X-ray afterglows of long-duration Gamma-Ray Bursts (GRBs) --observed by the X-Ray Telescope of the SWIFT satellite-- is precisely the one predicted by the Cannonball model of GRBs.

  10. Research on scheduling of robotic transient survey for Antarctic Survey Telescopes (AST3)

    Science.gov (United States)

    Liu, Qiang; Wei, Peng; Shang, Zhao-Hui; Ma, Bin; Hu, Yi

    2018-01-01

    Antarctic Survey Telescopes (AST3) are designed to be fully robotic telescopes at Dome A, Antarctica, which aim for highly efficient time-domain sky surveys as well as rapid response to special transient events (e.g., gamma-ray bursts, near-Earth asteroids, supernovae, etc.). Unlike traditional observations, a well-designed real-time survey scheduler is needed in order to implement an automatic survey in a very efficient, reliable and flexible way for the unattended telescopes. We present a study of the survey strategy for AST3 and implementation of its survey scheduler, which is also useful for other survey projects.

  11. Telescopes in education

    Science.gov (United States)

    Yessayian, Rick

    Imagine sitting in your classroom with your students and controlling a Research Grade 24 inch telescope. You control where it points, you control the duration of the exposure of a high grade CCD camera, and you control all of this within your school day, on a camera half way around the globe, in real time. You can hear the telescope moving, talk to the operator sitting atop historic Mt. Wilson Observatory in California. You might be looking at comets, asteroids, galaxies, nebulas or a host of other interesting celestial objects. Perhaps you have students that are up to a real challenge -- doing real science! Students in our program have contributed the discovery of a new variable star, to the Pluto Express project, to the search for supernovas, and the collection of images of intersecting galaxies. These are among the many possible projects you might choose from. The age and ability of your students are taken into account when you choose your project. Students from Kindergarten through Grade 12 have participated in this free program. A new robotic telescope was added at Mount Wilson in 1999. The telescope is a Celestron 14" SCT mounted on a Bisque Paramount GT-1100 with an Apogee AP-7 CCD camera (512X512 pixels). In the Spring of 2001, we duplicated the 14" robotic telescope configuration and placed it at the Las Campanas Observatory, Chile (operated by the Carnegie Observatories). I installed the system in late September, 2001, and we began testing. The system requires one more upgrade and some hardware adjustments, which I will complete in June, 2002. We duplicated another 14" robotic telescope, and sent it to Brisbane Australia in January, 2002. The grand opening of the telescope will be in August 2002.

  12. From Enigma to Tool: Gamma-Ray Burst Reveals Secrets of Host Galaxy

    Science.gov (United States)

    2001-05-01

    Five years ago, astronomers knew almost nothing about Gamma Ray Bursts. Now, a team of observers using the National Science Foundation's Very Large Array (VLA) radio telescope has used a gamma-ray burst as a powerful tool to unveil the nature of the galaxy in which it occurred, more than 7 billion light-years away. VLA Images of GRB980703 Host Galaxy "We believe that gamma-ray bursts may become one of the best available tools for studying the history of star formation in the universe," said Edo Berger, a graduate student at Caltech. Berger worked with Caltech astronomy professor Shri Kulkarni and Dale Frail, an astronomer at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, to study a gamma-ray burst first seen on July 3, 1998. The astronomers presented their results at the American Astronomical Society's meeting in Pasadena, CA. "For the first time, we've seen the host galaxy of a gamma-ray burst with a radio telescope," Berger said. "Previously, gamma-ray-burst host galaxies have been seen with optical telescopes, but detecting this galaxy with a radio telescope has given us new clues about the nature of the galaxy itself -- clues we couldn't have gotten any other way," he added. For example, based on optical-telescope studies, astronomers estimated that new stars are forming in the host galaxy at the rate of about the mass equivalent of 20 suns per year. However, data from the radio observations show that the actual star-formation rate is 25 times greater -- the mass equivalent of 500 suns per year. "With the VLA, we are seeing the entire region of star formation in this galaxy, including the areas so dusty that visible light can't get out," said Frail. Gamma-ray bursts are the most powerful explosions since the Big Bang. First discovered in 1967 by a satellite launched to monitor compliance with the atmospheric nuclear test ban treaty, gamma-ray bursts remained one of astronomy's premier mysteries for 30 years. For three decades

  13. The first interferometric detections of fast radio bursts

    Science.gov (United States)

    Caleb, M.; Flynn, C.; Bailes, M.; Barr, E. D.; Bateman, T.; Bhandari, S.; Campbell-Wilson, D.; Farah, W.; Green, A. J.; Hunstead, R. W.; Jameson, A.; Jankowski, F.; Keane, E. F.; Parthasarathy, A.; Ravi, V.; Rosado, P. A.; van Straten, W.; Venkatraman Krishnan, V.

    2017-07-01

    We present the first interferometric detections of fast radio bursts (FRBs), an enigmatic new class of astrophysical transient. In a 180-d survey of the Southern sky, we discovered three FRBs at 843 MHz with the UTMOST array, as a part of commissioning science during a major ongoing upgrade. The wide field of view of UTMOST (≈9 deg2) is well suited to FRB searches. The primary beam is covered by 352 partially overlapping fan-beams, each of which is searched for FRBs in real time with pulse widths in the range 0.655-42 ms, and dispersion measures ≤2000 pc cm-3. Detections of FRBs with the UTMOST array place a lower limit on their distances of ≈104 km (limit of the telescope near-field) supporting the case for an astronomical origin. Repeating FRBs at UTMOST or an FRB detected simultaneously with the Parkes radio telescope and UTMOST would allow a few arcsec localization, thereby providing an excellent means of identifying FRB host galaxies, if present. Up to 100 h of followup for each FRB has been carried out with the UTMOST, with no repeating bursts seen. From the detected position, we present 3σ error ellipses of 15 arcsec × 8.4° on the sky for the point of origin for the FRBs. We estimate an all-sky FRB rate at 843 MHz above a fluence F_lim of 11 Jy ms of ˜78 events sky-1 d-1 at the 95 per cent confidence level. The measured rate of FRBs at 843 MHz is two times higher than we had expected, scaling from the FRB rate at the Parkes radio telescope, assuming that FRBs have a flat spectral index and a uniform distribution in Euclidean space. We examine how this can be explained by FRBs having a steeper spectral index and/or a flatter logN-logF distribution than expected for a Euclidean Universe.

  14. Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; hide

    2013-01-01

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  15. Fermi-LAT observations of the gamma-ray burst GRB 130427A.

    Science.gov (United States)

    Ackermann, M; Ajello, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Bissaldi, E; Bonamente, E; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Burgess, J Michael; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cecchi, C; Chaplin, V; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cleveland, W; Cohen-Tanugi, J; Collazzi, A; Cominsky, L R; Connaughton, V; Conrad, J; Cutini, S; D'Ammando, F; de Angelis, A; DeKlotz, M; de Palma, F; Dermer, C D; Desiante, R; Diekmann, A; Di Venere, L; Drell, P S; Drlica-Wagner, A; Favuzzi, C; Fegan, S J; Ferrara, E C; Finke, J; Fitzpatrick, G; Focke, W B; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gehrels, N; Germani, S; Gibby, M; Giglietto, N; Giles, M; Giordano, F; Giroletti, M; Godfrey, G; Granot, J; Grenier, I A; Grove, J E; Gruber, D; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Horan, D; Hughes, R E; Inoue, Y; Jogler, T; Jóhannesson, G; Johnson, W N; Kawano, T; Knödlseder, J; Kocevski, D; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mayer, M; Mazziotta, M N; McEnery, J E; Michelson, P F; Mizuno, T; Moiseev, A A; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orienti, M; Paneque, D; Pelassa, V; Perkins, J S; Pesce-Rollins, M; Petrosian, V; Piron, F; Pivato, G; Porter, T A; Racusin, J L; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Roth, M; Ryde, F; Sartori, A; Parkinson, P M Saz; Scargle, J D; Schulz, A; Sgrò, C; Siskind, E J; Sonbas, E; Spandre, G; Spinelli, P; Tajima, H; Takahashi, H; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Winer, B L; Wood, K S; Yamazaki, R; Younes, G; Yu, H-F; Zhu, S J; Bhat, P N; Briggs, M S; Byrne, D; Foley, S; Goldstein, A; Jenke, P; Kippen, R M; Kouveliotou, C; McBreen, S; Meegan, C; Paciesas, W S; Preece, R; Rau, A; Tierney, D; van der Horst, A J; von Kienlin, A; Wilson-Hodge, C; Xiong, S; Cusumano, G; La Parola, V; Cummings, J R

    2014-01-03

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest γ-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  16. A New Clue in the Mystery of Fast Radio Bursts

    Science.gov (United States)

    Kohler, Susanna

    2017-06-01

    The origin of the mysterious fast radio bursts has eluded us for more than a decade. With the help of a particularly cooperative burst, however, scientists may finally be homing in on the answer to this puzzle.A Burst RepeatsThe host of FRB 121102 is placed in context in this Gemini image. [Gemini Observatory/AURA/NSF/NRC]More than 20 fast radio bursts rare and highly energetic millisecond-duration radio pulses have been observed since the first was discovered in 2007. FRB 121102, however, is unique in its behavior: its the only one of these bursts to repeat. The many flashes observed from FRB 121102 allowed us for the first time to follow up on the burst and hunt for its location.Earlier this year, this work led to the announcement that FRB 121102s host galaxy has been identified: a dwarf galaxy located at a redshift of z = 0.193 (roughly 3 billion light-years away). Now a team of scientists led by Cees Bassa (ASTRON, the Netherlands Institute for Radio Astronomy) has performed additional follow-up to learn more about this host and what might be causing the mysterious flashes.Hubble observation of the host galaxy. The object at the bottom right is a reference star. The blue ellipse marks the extended diffuse emission of the galaxy, the red circle marks the centroid of the star-forming knot, and the white cross denotes the location of FRB 121102 ad the associated persistent radio source. [Adapted from Bassa et al. 2017]Host ObservationsBassa and collaborators used the Hubble Space Telescope, the Spitzer Space Telecsope, and the Gemini North telecsope in Hawaii to obtain optical, near-infrared, and mid-infrared observations of FRB 121102s host galaxy.The authors determined that the galaxy is a dim, irregular, low-metallicity dwarf galaxy. Its resolved, revealing a bright star-forming region roughly 4,000 light-years across in the galaxys outskirts. Intriguingly, the persistent radio source associated with FRB 121102 falls directly within that star-forming knot

  17. FAST RADIO BURSTS AND RADIO TRANSIENTS FROM BLACK HOLE BATTERIES

    Energy Technology Data Exchange (ETDEWEB)

    Mingarelli, Chiara M. F. [TAPIR, MC 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Levin, Janna [Institute for Strings, Cosmology and Astroparticle Physics (ISCAP), Columbia University, New York, NY 10027 (United States); Lazio, T. Joseph W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  18. Analysis of Alerting System Failures in Commercial Aviation Accidents

    Science.gov (United States)

    Mumaw, Randall J.

    2017-01-01

    The role of an alerting system is to make the system operator (e.g., pilot) aware of an impending hazard or unsafe state so the hazard can be avoided or managed successfully. A review of 46 commercial aviation accidents (between 1998 and 2014) revealed that, in the vast majority of events, either the hazard was not alerted or relevant hazard alerting occurred but failed to aid the flight crew sufficiently. For this set of events, alerting system failures were placed in one of five phases: Detection, Understanding, Action Selection, Prioritization, and Execution. This study also reviewed the evolution of alerting system schemes in commercial aviation, which revealed naive assumptions about pilot reliability in monitoring flight path parameters; specifically, pilot monitoring was assumed to be more effective than it actually is. Examples are provided of the types of alerting system failures that have occurred, and recommendations are provided for alerting system improvements.

  19. Gamma-Ray Burst at the Extreme: "The Naked-Eye Burst" GRB 080319B

    Science.gov (United States)

    Woźniak, P. R.; Vestrand, W. T.; Panaitescu, A. D.; Wren, J. A.; Davis, H. R.; White, R. R.

    2009-01-01

    On 2008 March 19, the northern sky was the stage of a spectacular optical transient that for a few seconds remained visible to the naked eye. The transient was associated with GRB 080319B, a gamma-ray burst (GRB) at a luminosity distance of about 6 Gpc (standard cosmology), making it the most luminous optical object ever recorded by humankind. We present comprehensive sky monitoring and multicolor optical follow-up observations of GRB 080319B collected by the RAPTOR telescope network covering the development of the explosion and the afterglow before, during, and after the burst. The extremely bright prompt optical emission revealed features that are normally not detectable. The optical and gamma-ray variability during the explosion are correlated, but the optical flux is much greater than can be reconciled with single-emission mechanism and a flat gamma-ray spectrum. This extreme optical behavior is best understood as synchrotron self-Compton model (SSC). After a gradual onset of the gamma-ray emission, there is an abrupt rise of the prompt optical flux, suggesting that variable self-absorption dominates the early optical light curve. Our simultaneous multicolor optical light curves following the flash show spectral evolution consistent with a rapidly decaying red component due to large-angle emission and the emergence of a blue forward-shock component from interaction with the surrounding environment. While providing little support for the reverse shock that dominates the early afterglow, these observations strengthen the case for the universal role of the SSC mechanism in generating GRBs.

  20. Machine Learning Search for Gamma-Ray Burst Afterglows in Optical Images

    Science.gov (United States)

    Topinka, M.

    2016-06-01

    Thanks to the advances in robotic telescopes, time domain astronomy leads to a large number of transient events detected in images every night. Data mining and machine learning tools used for object classification are presented. The goal is to automatically classify transient events for both further follow-up by a larger telescope and for statistical studies of transient events. Special attention is given to the identification of gamma-ray burst afterglows. Machine learning techniques are used to identify GROND gamma-ray burst afterglow among the astrophysical objects present in the SDSS archival images based on the g'-r', r'-i' and i'-z' color indices. The performance of the support vector machine, random forest and neural network algorithms is compared. A joint meta-classifier, built on top of the individual classifiers, can identify GRB afterglows with the overall accuracy of ≳ 90%.

  1. Robotic and Survey Telescopes

    Science.gov (United States)

    Woźniak, Przemysław

    Robotic telescopes are revolutionizing the way astronomers collect their dataand conduct sky surveys. This chapter begins with a discussion of principles thatguide the process of designing, constructing, and operating telescopes andobservatories that offer a varying degree of automation, from instruments remotelycontrolled by observers to fully autonomous systems requiring no humansupervision during their normal operations. Emphasis is placed on designtrade-offs involved in building end-to-end systems intended for a wide range ofscience applications. The second part of the chapter contains descriptions ofseveral projects and instruments, both existing and currently under development.It is an attempt to provide a representative selection of actual systems thatillustrates state of the art in technology, as well as important ideas and milestonesin the development of the field. The list of presented instruments spans the fullrange in size starting from small all-sky monitors, through midrange robotic andsurvey telescopes, and finishing with large robotic instruments and surveys.Explosive growth of telescope networking is enabling entirely new modesof interaction between the survey and follow-up observing. Increasingimportance of standardized communication protocols and software is stressed.These developments are driven by the fusion of robotic telescope hardware,massive storage and databases, real-time knowledge extraction, and datacross-correlation on a global scale. The chapter concludes with examplesof major science results enabled by these new technologies and futureprospects.

  2. The Travelling Telescope

    Science.gov (United States)

    Murabona Oduori, Susan

    2015-08-01

    The telescope has been around for more than 400 years, and through good use of it scientists have made many astonishing discoveries and begun to understand our place in the universe. Most people, however, have never looked through one. Yet it is a great tool for cool science and observation especially in a continent and country with beautifully dark skies. The Travelling Telescope project aims to invite people outside under the stars to learn about those curious lights in the sky.The Travelling Telescope aims to promote science learning to a wide range of Kenyan schools in various locations exchanging knowledge about the sky through direct observations of celestial bodies using state of the art telescopes. In addition to direct observing we also teach science using various hands-on activities and astronomy software, ideal for explaining concepts which are hard to understand, and for a better grasp of the sights visible through the telescope. We are dedicated to promoting science using astronomy especially in schools, targeting children from as young as 3 years to the youth, teachers, their parents and members of the public. Our presentation focuses on the OAD funded project in rural coastal Kenya.

  3. Radio Telescope Reflectors

    Science.gov (United States)

    Baars, Jacob W. M.; Kärcher, Hans J.

    2017-11-01

    This book demonstrates how progress in radio astronomy is intimately linked to the development of reflector antennas of increasing size and precision. The authors describe the design and construction of major radio telescopes as those in Dwingeloo, Jodrell Bank, Parkes, Effelsberg and Green Bank since 1950 up to the present as well as millimeter wavelength telescopes as the 30m MRT of IRAM in Spain, the 50m LMT in Mexico and the ALMA submillimeter instrument. The advances in methods of structural design and coping with environmental influences (wind, temperature, gravity) as well as application of new materials are explained in a non-mathematical, descriptive and graphical way along with the story of the telescopes. Emphasis is placed on the interplay between astronomical and electromagnetic requirements and structural, mechanical and control solutions. A chapter on management aspects of large telescope projects closes the book. The authors address a readership with interest in the progress of engineering solutions applied to the development of radio telescope reflectors and ground station antennas for satellite communication and space research. The book will also be of interest to historians of science and engineering with an inclination to astronomy.

  4. The South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, J.E.; Ade, P.A.R.; Carlstrom, J.E.; Cho, H.M.; Crawford,T.; Dobbs, M.; Greer, C.H.; Halverson, N.W.; Holzapfel, W.L.; Lanting,T.M.; Lee, A.T.; Leitch, E.M.; Leong, J.; Lu, W.; Lueker, M.; Mehl, J.; Meyer, S.S.; Mohr, J.J.; Padin, S.; Plagge, T.; Pryke, C.; Runyan, M.C.; Schwan, D.; Sharp, M.K.; Spieler, H.; Staniszewski, Z.; Stark, A.A.

    2004-11-04

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10 m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over 4000 degrees for galaxy clusters using the Sunyaev-Zeldovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.

  5. A Search for TeV Counterparts to BATSE Gamma-Ray Bursts

    Science.gov (United States)

    Connanughton, V.; Akerlof, C. W.; Barthelmy, S.; Biller, S.; Boyle, P.; Fishman, G. J.; Meegan, C. A.

    1997-01-01

    Intense effort has gone into the observation of optical, radio, and X-ray gamma-ray burst (GRB) counterparts, either simultaneous to the burst or as quasi-steady lingering remnants. Here we report on a similar study at higher energies of 250 GeV and above using ground-based telescopes. The recent technical advances represented by the atmospheric Cherenkov imaging technique (Cawley & Weekes 1995) have opened up the field of gamma-ray astronomy above 250 GeV and raised the possibility that these techniques can be used with excellent fluence sensitivity in exploring the GRB phenomenon. Observations by the Whipple collaboration of nine BATSE positions, one acquired within 2 minutes of the reported BATSE burst time, using coordinates distributed through the BATSE Coordinates Distribution Network (BACODINE) are reported. No evidence of TeV emission is found, and upper limits to the high-energy delayed or extended emission of observed candidates are calculated.

  6. The SUrvey for Pulsars and Extragalactic Radio Bursts - I. Survey description and overview

    Science.gov (United States)

    Keane, E. F.; Barr, E. D.; Jameson, A.; Morello, V.; Caleb, M.; Bhandari, S.; Petroff, E.; Possenti, A.; Burgay, M.; Tiburzi, C.; Bailes, M.; Bhat, N. D. R.; Burke-Spolaor, S.; Eatough, R. P.; Flynn, C.; Jankowski, F.; Johnston, S.; Kramer, M.; Levin, L.; Ng, C.; van Straten, W.; Krishnan, V. Venkatraman

    2018-01-01

    We describe the Survey for Pulsars and Extragalactic Radio Bursts (SUPERB), an ongoing pulsar and fast transient survey using the Parkes radio telescope. SUPERB involves real-time acceleration searches for pulsars and single-pulse searches for pulsars and fast radio bursts. We report on the observational set-up, data analysis, multiwavelength/messenger connections, survey sensitivities to pulsars and fast radio bursts and the impact of radio frequency interference. We further report on the first 10 pulsars discovered in the project. Among these is PSR J1306-40, a millisecond pulsar in a binary system where it appears to be eclipsed for a large fraction of the orbit. PSR J1421-4407 is another binary millisecond pulsar; its orbital period is 30.7 d. This orbital period is in a range where only highly eccentric binaries are known, and expected by theory; despite this its orbit has an eccentricity of 10-5.

  7. Telescopes and Techniques

    CERN Document Server

    Kitchin, C R

    2013-01-01

    Telescopes and Techniques has proved itself in its first two editions, having become probably one of the most widely used astronomy texts, both for amateur astronomers and astronomy and astrophysics undergraduates. Both earlier editions of the book were widely used for introductory practical astronomy courses in many universities. In this Third Edition the author guides the reader through the mathematics, physics and practical techniques needed to use today's telescopes (from the smaller models to the larger instruments installed in many colleges) and how to find objects in the sky. Most of the physics and engineering involved is described fully and requires little prior knowledge or experience. Both visual and electronic imaging techniques are covered, together with an introduction to how data (measurements) should be processed and analyzed. A simple introduction to radio telescopes is also included. Brief coverage of the more advanced topics of photometry and spectroscopy are included, but mainly to enable ...

  8. Corot telescope (COROTEL)

    Science.gov (United States)

    Viard, Thierry; Mathieu, Jean-Claude; Fer, Yann; Bouzou, Nathalie; Spalinger, Etienne; Chataigner, Bruno; Bodin, Pierre; Magnan, Alain; Baglin, Annie

    2017-11-01

    COROTEL is the telescope of the COROT Satellite which aims at measuring stellar flux variations very accurately. To perform this mission, COROTEL has to be very well protected against straylight (from Sun and Earth) and must be very stable with time. Thanks to its high experience in this field, Alcatel Alenia Space has proposed, manufactured and tested an original telescope concept associated with a high baffling performance. Since its delivery to LAM (Laboratoire d'Astrophysique de Marseille, CNRS) the telescope has passed successfully the qualification tests at instrument level performed by CNES. Now, the instrument is mounted on a Proteus platform and should be launched end of 2006. The satellite should bring to scientific community for the first time precious data coming from stars and their possible companions.

  9. Configurable Aperture Space Telescope

    Science.gov (United States)

    Ennico, Kimberly; Vassigh, Kenny; Bendek, Selman; Young, Zion W; Lynch, Dana H.

    2015-01-01

    In December 2014, we were awarded Center Innovation Fund to evaluate an optical and mechanical concept for a novel implementation of a segmented telescope based on modular, interconnected small sats (satlets). The concept is called CAST, a Configurable Aperture Space Telescope. With a current TRL is 2 we will aim to reach TLR 3 in Sept 2015 by demonstrating a 2x2 mirror system to validate our optical model and error budget, provide strawman mechanical architecture and structural damping analyses, and derive future satlet-based observatory performance requirements. CAST provides an alternative access to visible andor UV wavelength space telescope with 1-meter or larger aperture for NASA SMD Astrophysics and Planetary Science community after the retirement of HST.

  10. Respiratory burst oxidase of fertilization.

    OpenAIRE

    Heinecke, J W; Shapiro, B M

    1989-01-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation...

  11. On the neutron bursts origin.

    CERN Document Server

    Stenkin, Yu V

    2002-01-01

    The origin of the neutron bursts in Extensive Air Showers (EAS) is explained using results of the experiments and CORSIKA based Monte-Carlo simulations. It is shown that events with very high neutron multiplicity observed last years in neutron monitors as well as in surrounding detectors, are caused by usual EAS core with primary energies > 1 PeV. No exotic processes were needed for the explanation.

  12. A FAST RADIO BURST IN THE DIRECTION OF THE CARINA DWARF SPHEROIDAL GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, V. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Shannon, R. M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Jameson, A., E-mail: v.vikram.ravi@gmail.com [Swinburne University of Technology, Centre for Astrophysics and Supercomputing, Mail H39, P.O. Box 218, VIC 3122 (Australia)

    2015-01-20

    We report the real-time discovery of a fast radio burst (FRB 131104) with the Parkes radio telescope in a targeted observation of the Carina dwarf spheroidal galaxy. The dispersion measure of the burst is 779 cm{sup –3} pc, exceeding predictions for the maximum line-of-sight Galactic contribution by a factor of 11. The temporal structure of the burst is characterized by an exponential scattering tail with a timescale of 2.0{sub −0.5}{sup +0.8} ms at 1582 MHz that scales as frequency to the power –4.4{sub −1.8}{sup +1.6} (all uncertainties represent 95% confidence intervals). We bound the intrinsic pulse width to be <0.64 ms due to dispersion smearing across a single spectrometer channel. Searches in 78 hr of follow-up observations with the Parkes telescope reveal no additional sporadic emission and no evidence for associated periodic radio emission. We hypothesize that the burst is associated with the Carina dwarf galaxy. Follow-up observations at other wavelengths are necessary to test this hypothesis.

  13. A Fast Radio Burst Every Second?

    Science.gov (United States)

    Kohler, Susanna

    2017-09-01

    far. [Fialkov Loeb 2017]The FRB luminosity functionFRBs may all have the same intrinsic brightness (like Type Ia supernovae, for instance). Alternatively, there may be many more faint and dim FRBs than bright ones (like the distribution of galaxy luminosities). Thisdifference affects the number of FRBs we could detect.The host galaxy populationAre FRBs most commonly hosted by low-mass galaxies like FRB 121102? Or do they occur in high-mass galaxies as well? This affects the number of FRBs we would expect to observe at different redshifts.Future HopeBy exploring a range of models that vary these three factors, Fialkov and Loeb find estimates for the rate of FRBs that would appear inthe 500 MHz3.5 GHz frequency band probed by observatories like Parkes, Arecibo, and the Australian Square Kilometre Array Pathfinder (ASKAP).Fialkov and Loeb find that, when we account for faint sources, one FRB may occur per second across the sky in this band. The authors show that future low-frequency radio telescopes with higher sensitivity, such as the Square Kilometre Array, should be able to detect many more of these sources, helping us to differentiate between the models and narrow down the properties of the bursts and their hosts. This, in turn, may finally reveal what causes these mysterious signals.CitationAnastasia Fialkov and Abraham Loeb 2017 ApJL 846 L27. doi:10.3847/2041-8213/aa8905

  14. The Liverpool Telescope

    Science.gov (United States)

    Smith, Robert J.; Bates, S. D.; Clay, Neil R.; Fraser, Stephen N.; Marchant, J. M.; Mottram, C. J.; Steele, I. A.; Tomlinson, M. D.

    2011-03-01

    The Liverpool Telescope (LT) is a fully robotic 2m optical telescope at a world-class observatory site. It runs autonomously without direct human control either on site or remotely. It is not operated primarily for a single science project, but rather is a common-user facility, time allocated by an open, peer-review process and conducting a variety of optical and IR imaging, spectroscopic and polarimetric programs. This paper describes some of aspects of the site infrastructure and instrument suite designed specifically to support robust and reliable unsupervised operations. Aside from the telescope hardware, the other aspect of robotic operations is the mechanisms whereby users interact with the telescope and its automated scheduler. We describe how these have been implemented for the LT. Observing routinely since 2004, the LT has demonstrated it is possible to operate a large, common-user robotic observatory. Making the most of the flexibility afforded by fully robotic operations, development continues in collaboration with both observers and other observatories to develop observing modes to enable new science across the broad discipline of time-domain astrophysics.

  15. Exploring Galileo's Telescope

    Science.gov (United States)

    Straulino, Samuele; Terzuoli, Alessandra

    2010-01-01

    In the first months of 2009, the International Year of Astronomy, the authors developed an educational project for middle-level students connected with the first astronomical discoveries that Galileo Galilei (1564-1642) made 400 years ago. The project included the construction of a basic telescope and the observation of the Moon. The project, if…

  16. Taiwan Automated Telescope Network

    Directory of Open Access Journals (Sweden)

    Dean-Yi Chou

    2010-01-01

    can be operated either interactively or fully automatically. In the interactive mode, it can be controlled through the Internet. In the fully automatic mode, the telescope operates with preset parameters without any human care, including taking dark frames and flat frames. The network can also be used for studies that require continuous observations for selected objects.

  17. A Multi-telescope Campaign on FRB 121102: Implications for the FRB Population

    Science.gov (United States)

    Law, C. J.; Abruzzo, M. W.; Bassa, C. G.; Bower, G. C.; Burke-Spolaor, S.; Butler, B. J.; Cantwell, T.; Carey, S. H.; Chatterjee, S.; Cordes, J. M.; Demorest, P.; Dowell, J.; Fender, R.; Gourdji, K.; Grainge, K.; Hessels, J. W. T.; Hickish, J.; Kaspi, V. M.; Lazio, T. J. W.; McLaughlin, M. A.; Michilli, D.; Mooley, K.; Perrott, Y. C.; Ransom, S. M.; Razavi-Ghods, N.; Rupen, M.; Scaife, A.; Scott, P.; Scholz, P.; Seymour, A.; Spitler, L. G.; Stovall, K.; Tendulkar, S. P.; Titterington, D.; Wharton, R. S.; Williams, P. K. G.

    2017-11-01

    We present results of the coordinated observing campaign that made the first subarcsecond localization of a fast radio burst, FRB 121102. During this campaign, we made the first simultaneous detection of an FRB burst using multiple telescopes: the VLA at 3 GHz and the Arecibo Observatory at 1.4 GHz. Of the nine bursts detected by the Very Large Array at 3 GHz, four had simultaneous observing coverage at other observatories at frequencies from 70 MHz to 15 GHz. The one multi-observatory detection and three non-detections of bursts seen at 3 GHz confirm earlier results showing that burst spectra are not well modeled by a power law. We find that burst spectra are characterized by a ∼500 MHz envelope and apparent radio energy as high as 1040 erg. We measure significant changes in the apparent dispersion between bursts that can be attributed to frequency-dependent profiles or some other intrinsic burst structure that adds a systematic error to the estimate of dispersion measure by up to 1%. We use FRB 121102 as a prototype of the FRB class to estimate a volumetric birth rate of FRB sources {R}{FRB}≈ 5× {10}-5/{N}r Mpc‑3 yr‑1, where N r is the number of bursts per source over its lifetime. This rate is broadly consistent with models of FRBs from young pulsars or magnetars born in superluminous supernovae or long gamma-ray bursts if the typical FRB repeats on the order of thousands of times during its lifetime.

  18. Fuzzy-Based Adaptive Hybrid Burst Assembly Technique for Optical Burst Switched Networks

    Directory of Open Access Journals (Sweden)

    Abubakar Muhammad Umaru

    2014-01-01

    Full Text Available The optical burst switching (OBS paradigm is perceived as an intermediate switching technology for future all-optical networks. Burst assembly that is the first process in OBS is the focus of this paper. In this paper, an intelligent hybrid burst assembly algorithm that is based on fuzzy logic is proposed. The new algorithm is evaluated against the traditional hybrid burst assembly algorithm and the fuzzy adaptive threshold (FAT burst assembly algorithm via simulation. Simulation results show that the proposed algorithm outperforms the hybrid and the FAT algorithms in terms of burst end-to-end delay, packet end-to-end delay, and packet loss ratio.

  19. Giant Magellan Telescope: overview

    Science.gov (United States)

    Johns, Matt; McCarthy, Patrick; Raybould, Keith; Bouchez, Antonin; Farahani, Arash; Filgueira, Jose; Jacoby, George; Shectman, Steve; Sheehan, Michael

    2012-09-01

    The Giant Magellan Telescope (GMT) is a 25-meter optical/infrared extremely large telescope that is being built by an international consortium of universities and research institutions. It will be located at the Las Campanas Observatory, Chile. The GMT primary mirror consists of seven 8.4-m borosilicate honeycomb mirror segments made at the Steward Observatory Mirror Lab (SOML). Six identical off-axis segments and one on-axis segment are arranged on a single nearly-paraboloidal parent surface having an overall focal ratio of f/0.7. The fabrication, testing and verification procedures required to produce the closely-matched off-axis mirror segments were developed during the production of the first mirror. Production of the second and third off-axis segments is underway. GMT incorporates a seven-segment Gregorian adaptive secondary to implement three modes of adaptive-optics operation: natural-guide star AO, laser-tomography AO, and ground-layer AO. A wide-field corrector/ADC is available for use in seeing-limited mode over a 20-arcmin diameter field of view. Up to seven instruments can be mounted simultaneously on the telescope in a large Gregorian Instrument Rotator. Conceptual design studies were completed for six AO and seeing-limited instruments, plus a multi-object fiber feed, and a roadmap for phased deployment of the GMT instrument suite is being developed. The partner institutions have made firm commitments for approximately 45% of the funds required to build the telescope. Project Office efforts are currently focused on advancing the telescope and enclosure design in preparation for subsystem- and system-level preliminary design reviews which are scheduled to be completed in the first half of 2013.

  20. Simultaneous observations of solar sporadic radio emission by the radio telescopes UTR-2, URAN-2 and NDA within the frequency range 8-41MHz

    Science.gov (United States)

    Melnik, V. N.; Konovalenko, A. A.; Rucker, H. O.; Brazhenko, A. I.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Denis, L.; Bulatzen, V. G.; Frantzusenko, A. V.; Stanislavskyy, A. A.

    2012-04-01

    From 25 June till 12 August 2011 sporadic solar radio emission was observed simultaneously by three separate radio telescopes: UTR-2 (Kharkov, Ukraine), URAN-2 (Poltava, Ukraine) and NDA (Nancay, France). During these observations several type II bursts with double and triple harmonics were registered, as well as type II bursts with complex herringbone structure. The events of particular interest were type II bursts registered on 9 and 11 August 2011. These bursts had opposite sign of circular polarization at different parts of their dynamic spectra. In our opinion we registered the emissions, which came from the different parts of the shock propagating through the solar corona. We have observed also groups of type III bursts merged into one burst, type III bursts with triple harmonics and type III bursts with "split" polarization. In addition some unusual solar bursts were registered: storms of strange narrow-band (up to 500kHz) bursts with high polarization degree (about 80%), decameter spikes of extremely short durations (200-300ms), "tadpole-like" bursts with durations of 1-2s and polarization degree up to 60%.

  1. The Common Alerting Protocol (CAP) adaption in National Early Warning Alerting Systems of China

    Science.gov (United States)

    Li, Chao

    2017-04-01

    The Common Alerting Protocol (CAP) [1] is an XML-based data format for exchanging public warnings and emergencies between alerting technologies. In China, from local communities to entire nations, there was a patchwork of specialized hazard public alerting systems. And each system was often designed just for certain emergency situations and for certain communications media. Application took place in the NEWAS (National Early Warning Alerting Systems) [2]project where CAP serves as central message to integrate all kind of hazard situations, including the natural calamity, accident disaster, public health emergency , social safety etc. Officially operated on May 2015, NEWAS now has completed docking work with 14 departments including civil administration, safety supervision, forestry, land, water conservancy, earthquake, traffic, meteorology, agriculture, tourism, food and drug supervision, public security and oceanic administration. Thus, several items in CAP has been modified, redefined and extended according to the various grading standards and publishing strategies, as well as the characteristics of Chinese Geocoding. NEWAS successfully delivers information to end users through 4 levels (i.e. State, province, prefecture and county) structure and by various means. [1] CAP, http://www.oasis-emergency.org/cap [2] http://www.12379.cn/

  2. Optical Space Telescope Assembly Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Space Telescope Assembly (OSTA) task is to demonstrate the technology readiness of assembling large space telescopes on orbit in 2015. This task is an...

  3. Sleepiness and alertness in American industries

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, R.M.; Dillingham, J.; Dement, W.C.

    1989-01-01

    Recent evidence that industrial accidents may be caused in part by shiftworkers' lack of alertness has caused growing concern at the US Nuclear Regulatory Commission and within the scientific community. The purpose of the study reported in this paper was threefold: (1) Is sleepiness on the job specific to utility plants (2) Are performance and safety problems caused by sleepiness specific to utility plants (3) Are specific shift schedules associated with a higher prevalence of sleepiness Findings indicate sleepiness on the job among shiftworkers is a widespread problem, not limited to the nuclear power industry. The most common solution in American industry is to overstaff each shift and discipline sleeping employees. Results show this is not effective. A more proactive solution is recommended including some of the following: (1) Provide employees education to assist adjustment to shiftwork. (2) Design and implement shift schedules that are more compatible with human physiological capabilities. (3) Allow officially sanctioned napping on shift as is done in Japan. (4) Divide 6-, 8-, or 12-h shifts into smaller blocks of 2 to 3 h of primary duty. (5) make the environment where employees work more conductive to alertness. (6) Develop a firehouse type of schedule where some employees sleep throughout the night, but are awakened if operational problems arise. (7) Provide incentives to employees to adjust their life style to the night shift and reward them with time off.

  4. Validation of the CME Geomagnetic Forecast Alerts Under the COMESEP Alert System

    Science.gov (United States)

    Dumbović, Mateja; Srivastava, Nandita; Rao, Yamini K.; Vršnak, Bojan; Devos, Andy; Rodriguez, Luciano

    2017-08-01

    Under the European Union 7th Framework Programme (EU FP7) project Coronal Mass Ejections and Solar Energetic Particles (COMESEP, http://comesep.aeronomy.be), an automated space weather alert system has been developed to forecast solar energetic particles (SEP) and coronal mass ejection (CME) risk levels at Earth. The COMESEP alert system uses the automated detection tool called Computer Aided CME Tracking (CACTus) to detect potentially threatening CMEs, a drag-based model (DBM) to predict their arrival, and a CME geoeffectiveness tool (CGFT) to predict their geomagnetic impact. Whenever CACTus detects a halo or partial halo CME and issues an alert, the DBM calculates its arrival time at Earth and the CGFT calculates its geomagnetic risk level. The geomagnetic risk level is calculated based on an estimation of the CME arrival probability and its likely geoeffectiveness, as well as an estimate of the geomagnetic storm duration. We present the evaluation of the CME risk level forecast with the COMESEP alert system based on a study of geoeffective CMEs observed during 2014. The validation of the forecast tool is made by comparing the forecasts with observations. In addition, we test the success rate of the automatic forecasts (without human intervention) against the forecasts with human intervention using advanced versions of the DBM and CGFT (independent tools available at the Hvar Observatory website, http://oh.geof.unizg.hr). The results indicate that the success rate of the forecast in its current form is unacceptably low for a realistic operation system. Human intervention improves the forecast, but the false-alarm rate remains unacceptably high. We discuss these results and their implications for possible improvement of the COMESEP alert system.

  5. Uzaybimer Radio Telescope Control System

    Science.gov (United States)

    Balbay, R.; Öz, G. K.; Arslan, Ö.; Özeren, F. F.; Küçük, İ.

    2016-12-01

    A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBİMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.

  6. Hardness/intensity correlations among BATSE bursts

    Science.gov (United States)

    Paciesas, William S.; Pendleton, Geoffrey N.; Kouveliotou, Chryssa; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.

    1992-01-01

    Conclusions about the nature of gamma-ray bursts derived from the size-frequency distribution may be altered if a significant correlation exists between burst intensity and spectral shape. Moreover, if gamma-ray bursts have a cosmological origin, such a correlation may be expected to result from the expansion of the universe. We have performed a rudimentary search of the BATSE bursts for hardness/intensity correlations. The range of spectral shapes was determined for each burst by computing the ratio of the intensity in the range 100-300 keV to that in 55-300 keV. We find weak evidence for the existence of a correlation, the strongest effect being present when comparing the maximum hardness ratio for each burst with its maximum rate.

  7. Observations of Gamma-Ray Bursts

    Science.gov (United States)

    Fishman, Gerald J.

    1999-01-01

    Gamma-ray bursts are now generally believed to originate from cosmological distances and represent the largest known explosions in the Universe. These lectures will describe the temporal and spectral characteristic of gamma-ray bursts, their intensity and sky distribution, and other observed characteristics in the gamma-ray region, primarily from data obtained with the BATSE experiment on the Compton Observatory. A summary of recent discoveries and observations in other wavelength regions will also be presented, along with their implications for models of the burst emission mechanism. Various possibilities and models for the energy source(s) of gamma-ray bursts will be described.

  8. The Photometry Pipeline of the Watcher Robotic Telescope

    Directory of Open Access Journals (Sweden)

    A. Ferrero

    2010-01-01

    Full Text Available The Watcher robotic telescope was developed primarily to perform rapid optical follow-up observations of Gamma-Ray Bursts (GRBs. Secondary scientific goals include blazar monitoring and variable star studies. An automated photometry pipeline to rapidly analyse data from Watcher has been implemented. Details of the procedures to get image zero-point, source instrumental measurement, and limiting magnitude are presented. Sources of uncertainty are assessed and the performance of the pipeline is tested by comparison with a number of catalogue sources.

  9. Galileo's wondrous telescope

    Science.gov (United States)

    Cartlidge, Edwin

    2008-06-01

    If you need reminding of just how wrong the great and the good can be, take a trip to the Museum of the History of Science in Florence, Italy. The museum is staging an exhibition entitled "Galileo's telescope - the instrument that changed the world" to mark the 400th anniversary this year of Galileo Galilei's revolutionary astronomical discoveries, which were made possible by the invention of the telescope. At the start of the 17th century, astronomers assumed that all the planets and the stars in the heavens had been identified and that there was nothing new for them to discover, as the exhibition's curator, Giorgio Strano, points out. "No-one could have imagined what wondrous new things were about to be revealed by an instrument created by inserting two eyeglass lenses into the ends of a tube," he adds.

  10. The Bionic Telescope

    Science.gov (United States)

    Woolf, Neville

    2009-05-01

    Four hundred years after children in a spectacle makers workshop accidentally discovered the telescope, the development of this device has been a continuous replacement of the ``natural'' by the deliberate. The human eye is gone. The lens is gone. The tube is gone. The dome is on the verge of going. The size of the optics are ceasing to be set by transportation limits. Adaptive optics are preferred to stable optics. We deliberately break the Lagrange invariant. We focus on lasers instead of stars, and natural observing environments are being replaced by adaptive environments. The goals for the new ground based telescope encompass the oldest and newest ideas, to find signs of life elsewhere, and to find how all the universe developed.

  11. Calibrating the Athena telescope

    Science.gov (United States)

    de Bruijne, J.; Guainazzi, M.; den Herder, J.; Bavdaz, M.; Burwitz, V.; Ferrando, P.; Lumb, D.; Natalucci, L.; Pajot, F.; Pareschi, G.

    2017-10-01

    Athena is ESA's upcoming X-ray mission, currently set for launch in 2028. With two nationally-funded, state-of-the-art instruments (a high-resolution spectrograph named X-IFU and a wide-field imager named WFI), and a telescope collecting area of 1.4-2 m^2 at 1 keV, the calibration of the spacecraft is a challenge in itself. This poster presents the current (spring 2017) plan of how to calibrate the Athena telescope. It is based on a hybrid approach, using bulk manufacturing and integration data as well as dedicated calibration measurements combined with a refined software model to simulate the full response of the optics.

  12. Everyday Radio Telescope

    CERN Document Server

    Mandal, Pranshu; Kumar, Pratik; Yelikar, Anjali; Soni, Kanchan; T, Vineeth Krishna

    2016-01-01

    We have developed an affordable, portable college level radio telescope for amateur radio astronomy which can be used to provide hands-on experience with the fundamentals of a radio telescope and an insight into the realm of radio astronomy. With our set-up one can measure brightness temperature and flux of the Sun at 11.2 GHz and calculate the beam width of the antenna. The set-up uses commercially available satellite television receiving system and parabolic dish antenna. We report the detection of point sources like Saturn and extended sources like the galactic arm of the Milky way. We have also developed python pipeline, which are available for free download, for data acquisition and visualization.

  13. A Fast Radio Burst Occurs Every Second throughout the Observable Universe

    Science.gov (United States)

    Fialkov, Anastasia; Loeb, Abraham

    2017-09-01

    Recent multi-telescope observations of the repeating fast radio burst (FRB) FRB 121102 reveal a Gaussian-like spectral profile and associate the event with a dwarf metal-poor galaxy at a cosmological redshift of 0.19. Assuming that this event represents the entire FRB population, we make predictions for the expected number counts of FRBs observable by future radio telescopes between 50 MHz and 3.5 GHz. We vary our model assumptions to bracket the expected rate of FRBs and find that it exceeds one FRB per second per sky when accounting for faint sources. We show that future low-frequency radio telescopes, such as the Square Kilometre Array, could detect more than one FRB per minute over the entire sky originating from the epoch of reionization.

  14. [Galileo and his telescope].

    Science.gov (United States)

    Strebel, Christoph

    2006-01-01

    Galileo's publication of observations made with his newly reinvented telescope provoked a fierce debate. In April 1610 Martinus Horky, a young Bohemian astronomer, had an opportunity to make his own observations with Galileo's telescope in the presence of Antonio Magini and other astronomers. Horky and the other witnesses denied the adequacy of Galileo's telescope and therefore the bona fides of his discoveries. Kepler conjectured Horky as well as all his witnesses to be myopic. But Kepler's objection could not stop the publication of Horky's Peregrinatio contra nuncium sidereum (Modena, 1610), the first printed refutation of Galileo's Sidereus nuncius. In his treatise, Horky adresses four questions: 1) Do the four newly observed heavenly bodies actually exist? Horky denies their existence on various grounds: a) God, as every astronomer teaches, has created only seven moveable heavenly bodies and astronomical knowledge originates in God, too. b) Heavenly bodies are either stars or planets. Galileo's moveable heavenly bodies fit into neither category. c) If they do exist, why have they not already been observed by other scholars? Horky concludes that there are no such heavenly bodies. 2) What are these phenomena? They are purely artefactual, and produced by Galileo's telescope. 3) How are they like? Galileo's "stars" are so small as to be almost invisible. Galileo claims that he has measured their distances from each other. This however is impossible due to their diminutive size and other observational problems. Hence, Galileo's claim is a further proof that he is a fraud. 4) Why are they? For Galileo they are a chance to earn money but for astronomers like Horky they are a reason to offer thanks and honour to God. Horky's treatise was favourably received by the enemies of Galileo. But Kepler's critique was devastating. After calling on Kepler in Prague, Horky had to revoke the contents of his book.

  15. The On-Site Analysis of the Cherenkov Telescope Array

    CERN Document Server

    Bulgarelli, Andrea; Zoli, Andrea; Aboudan, Alessio; Rodríguez-Vázquez, Juan José; De Cesare, Giovanni; De Rosa, Adriano; Maier, Gernot; Lyard, Etienne; Bastieri, Denis; Lombardi, Saverio; Tosti, Gino; Bergamaschi, Sonia; Beneventano, Domenico; Lamanna, Giovanni; Jacquemier, Jean; Kosack, Karl; Antonelli, Lucio Angelo; Boisson, Catherine; Borkowski, Jerzy; Buson, Sara; Carosi, Alessandro; Conforti, Vito; Colomé, Pep; Reyes, Raquel de los; Dumm, Jon; Evans, Phil; Fortson, Lucy; Fuessling, Matthias; Gotz, Diego; Graciani, Ricardo; Gianotti, Fulvio; Grandi, Paola; Hinton, Jim; Humensky, Brian; Inoue, Susumu; Knödlseder, Jürgen; Flour, Thierry Le; Lindemann, Rico; Malaguti, Giuseppe; Markoff, Sera; Marisaldi, Martino; Neyroud, Nadine; Nicastro, Luciano; Ohm, Stefan; Osborne, Julian; Oya, Igor; Rodriguez, Jerome; Rosen, Simon; Ribo, Marc; Tacchini, Alessandro; Schüssler, Fabian; Stolarczyk, Thierry; Torresi, Eleonora; Testa, Vincenzo; Wegner, Peter

    2015-01-01

    The Cherenkov Telescope Array (CTA) observatory will be one of the largest ground-based very high-energy gamma-ray observatories. The On-Site Analysis will be the first CTA scientific analysis of data acquired from the array of telescopes, in both northern and southern sites. The On-Site Analysis will have two pipelines: the Level-A pipeline (also known as Real-Time Analysis, RTA) and the level-B one. The RTA performs data quality monitoring and must be able to issue automated alerts on variable and transient astrophysical sources within 30 seconds from the last acquired Cherenkov event that contributes to the alert, with a sensitivity not worse than the one achieved by the final pipeline by more than a factor of 3. The Level-B Analysis has a better sensitivity (not be worse than the final one by a factor of 2) and the results should be available within 10 hours from the acquisition of the data: for this reason this analysis could be performed at the end of an observation or next morning. The latency (in part...

  16. Fast radio burst event rate counts - I. Interpreting the observations

    Science.gov (United States)

    Macquart, J.-P.; Ekers, R. D.

    2018-02-01

    The fluence distribution of the fast radio burst (FRB) population (the `source count' distribution, N (>F) ∝Fα), is a crucial diagnostic of its distance distribution, and hence the progenitor evolutionary history. We critically reanalyse current estimates of the FRB source count distribution. We demonstrate that the Lorimer burst (FRB 010724) is subject to discovery bias, and should be excluded from all statistical studies of the population. We re-examine the evidence for flat, α > -1, source count estimates based on the ratio of single-beam to multiple-beam detections with the Parkes multibeam receiver, and show that current data imply only a very weak constraint of α ≲ -1.3. A maximum-likelihood analysis applied to the portion of the Parkes FRB population detected above the observational completeness fluence of 2 Jy ms yields α = -2.6_{-1.3}^{+0.7 }. Uncertainties in the location of each FRB within the Parkes beam render estimates of the Parkes event rate uncertain in both normalizing survey area and the estimated post-beam-corrected completeness fluence; this uncertainty needs to be accounted for when comparing the event rate against event rates measured at other telescopes.

  17. GRB 081029: A Gamma-Ray Burst with a Multi-Component Afterglow

    Science.gov (United States)

    Holland, Stephen T.; De Pasquale, Massimiliano; Mao, Jirong; Sakamoto, Takanori; Schady, Patricia; Covino, Stefano; Fan, Yi-Zhong; Jin, Zhi-Ping; D'Avanzo, Paolo; Antonelli, Angelo; hide

    2012-01-01

    We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift Ultra Violet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3-m telescopes to construct a detailed data set extending from 86 s to approx.100,000 s after the BAT trigger. Our data covers a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18,000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.injection

  18. Short arc orbit determination and Gaia alerts

    Science.gov (United States)

    Spoto, Federica; Tanga, Paolo; Del Vigna, Alessio; Carry, Benoit; Thuillot, William; David, Pedro; Mignard, Francois; Milani, Andrea; Tommei, Giacomo

    2017-10-01

    Since October 2016, the short term (ST) processing of Solar System Objects (SSOs) by Gaia is up and running, and it has produced almost 600 alerts. A crucial point in the chain is the possibility of performing a short arc orbit determination as soon as the object has been detected, which allows the follow up of the object from the ground.The method we present has been recentely developed for two mainreasons: 1) search for imminent impactors within the NEO - Confirmation Page(imminent impactors are asteroids that could impact the Earth infew days from their discovery) 2) validation of the SSO-ST Gaia pipeline.We show some good confirmations on objects that could have been discovered by Gaia, and some properties of the Gaia astrometry for the short term.

  19. NAPS as an Alertness Management Strategy

    Science.gov (United States)

    Rosekind, Mark R.; Smith, Roy M.; Miller, Donna L.; Co, Elizabeth L.; Gregory, Kevin B.; Gander, Philippa H.; Lebacqz, J. Victor

    2001-01-01

    Today, 24-hour operations are necessary to meet the demands of our society and the requirements of our industrialized global economy. These around-the-clock demands pose unique physiological challenges for the humans who remain central to safe and productive operations. Optimal alertness and performance are critical factors that are increasingly challenged by unusual, extended, or changing work/rest schedules. Technological advancements and automated systems can exacerbate the challenges faced by the human factor in these environments. Shift work, transportation demands, and continuous operations engender sleep loss and circadian disruption. Both of these physiological factors can lead to increased sleepiness, decreased performance, and a reduced margin of safety. These factors can increase vulnerability to incidents and accidents in operational settings. The consequences can have both societal effects (e.g., major destructive accidents such as Three Mile Island, Exxon Valdez, Bhopal) and personal effects (e.g., an accident driving home after a night shift).

  20. The BOOTES-5 telescope at San Pedro Martir National Astronomical Observatory, Mexico

    Science.gov (United States)

    Hiriart, D.; Valdez, J.; Martínez, B.; García, B.; Cordova, A.; Colorado, E.; Guisa, G.; Ochoa, J. L.; Nuñez, J. M.; Ceseña, U.; Cunniffe, R.; Murphy, D.; Lee, W.; Park, Il H.; Castro-Tirado, A. J.

    2016-12-01

    BOOTES-5 is the fifth robotic observatory of the international network of robotic telescopes BOOTES (Burst Observer and Optical Transient Exploring Optical System). It is located at the National Astronomical Observatory at Sierra San Pedro Martir, Baja California, Mexico. It was dedicated on November 26, 2015 and it is in the process of testing. Its main scientific objective is the observation and monitoring of the optic counterparts of gamma-ray bursts as quickly as possible once they have been detected from space or other ground-based observatories. BOOTES-5 fue nombrado Telescopio Javier Gorosabel en memoria del astrónomo español Javier Gorosabel Urkia.

  1. SOAR Telescope Progress Report

    Science.gov (United States)

    Sebring, T.; Cecil, G.; Krabbendam, V.

    1999-12-01

    The 4.3m SOAR telescope is fully funded and under construction. A partnership between the country of Brazil, NOAO, Michigan State University, and the University of North Carolina at Chapel Hill, SOAR is being designed for high-quality imaging and imaging spectroscopy in the optical and near-IR over a field of view up to 12' diameter. US astronomers outside MSU and UNC will access 30% of the observing time through the standard NOAO TAC process. The telescope is being designed to support remote and synoptic observations. First light is scheduled for July 2002 at Cerro Pachon in Chile, a site with median seeing of 2/3" at 500 nm. The telescope will be operated by CTIO. Corning Inc. has fused the mirror blanks from boules of ULE glass. RSI in Richardson, Texas and Raytheon Optical Systems Inc. in Danbury, Conn. are designing and will fabricate the mount and active optics systems, respectively. The mount supports an instrument payload in excess of 5000 kg, at 2 Nasmyth locations and 3 bent Cass. ports. The mount and facility building have space for a laser to generate an artificial AO guide star. LabVIEW running under the Linux OS on compactPCI hardware has been adopted to control all telescope, detector, and instrument systems. The primary mirror is 10 cm thick and will be mounted on 120 electro-mechanical actuators to maintain its ideal optical figure at all elevations. The position of the light-weighted secondary mirror is adjusted to maintain collimation through use of a Shack-Hartmann wavefront sensor. The tertiary mirror feeds instruments and also jitters at up to 50 Hz to compensate for telescope shake and atmosphere wavefront tilt. The dome is a steel framework, with fiberglass panels. Air in the observing volume will be exchanged with that outside every few minutes by using large fans under computer control. All systems will be assembled and checked at the manufacturer's facility, then shipped to Chile. A short integration period is planned, and limited science

  2. A new method for determining a sector alert

    Science.gov (United States)

    2008-09-29

    The Traffic Flow Management System (TFMS) currently declares an alert for any 15-minute interval in which the predicted demand exceeds the Monitor/Alert Parameter (MAP) for any airport, sector, or fix. For a sector, TFMS predicts the demand for each ...

  3. Understanding Electronic AKI Alerts: Characterization by Definitional Rules

    Directory of Open Access Journals (Sweden)

    Jennifer Holmes

    2017-05-01

    Discussion: Rule 1 could only be invoked for stage 1 alerts and was associated with acute on chronic kidney disease acquired in hospital. Rule 2 was also associated with hospital-acquired AKI and had the highest mortality and nonrecovery. Rule 3 was the commonest cause of an alert and was associated with community-acquired AKI.

  4. Abonnez-vous aux alertes de financement | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Abonnez-vous aux alertes de financement. Abonnez-vous maintenant et recevez des alertes sur les nouvelles subventions directement par courriel. Nom (requis). Courriel (requis). Nous cherchons à déterminer qui consulte le bulletin. Laquelle des descriptions suivantes vous correspond le mieux ? (requis). Choisir, Autre ...

  5. 47 CFR 10.320 - Provider alert gateway requirements.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Provider alert gateway requirements. 10.320... System Architecture § 10.320 Provider alert gateway requirements. This section specifies the functions... CMS provider gateways. (a) General. The CMS provider gateway must provide secure, redundant, and...

  6. Aircraft Alerting Systems Criteria Study. Volume 1. Collation and Analysis of Aircraft Alerting Systems Data

    Science.gov (United States)

    1977-05-01

    that they have learned previously In other situations, The effect of a previously learned skill on performance in a new situation is called transfer...IMPORTANCE TO REQUIRE THEIR USE, 171 L TABLE E-1 (CONT) ALERTING SYSTEM REQUIREMENTS FOUND IN ARP 450 2,2.7 TACTUAL SIGNALS: TACTUAL SIGNALS MAY BE...2.12 TACTUAL SIGNALS PERCEPTIBILITY: THE INTENSITY OF TACTICAL SIGNALS SHALL BE SUCH AS TO ASSURE THEIR PERCEPTIBILITY UNDER ALL CONDITIONS. 2.13 TACTUAL

  7. Coupling and noise induced spiking-bursting transition in a parabolic bursting model

    Science.gov (United States)

    Ji, Lin; Zhang, Jia; Lang, Xiufeng; Zhang, Xiuhui

    2013-03-01

    The transition from tonic spiking to bursting is an important dynamic process that carry physiologically relevant information. In this work, coupling and noise induced spiking-bursting transition is investigated in a parabolic bursting model with specific discussion on their cooperation effects. Fast/slow analysis shows that weak coupling may help to induce the bursting by changing the geometric property of the fast subsystem so that the original unstable periodical solution are stabilized. It turned out that noise can play the similar stabilization role and induce bursting at appropriate moderate intensity. However, their cooperation may either strengthen or weaken the overall effect depending on the choice of noise level.

  8. Photospheric radius expansion during magnetar bursts

    NARCIS (Netherlands)

    Watts, A.L.; Kouveliotou, C.; van der Horst, A.J.; Göğüş, E.; Kaneko, Y.; van der Klis, M.; Wijers, R.A.M.J.; Harding, A.K.; Baring, M.G.

    2010-01-01

    On 2008 August 24 the new magnetar SGR 0501+4516 (discovered by Swift) emitted a bright burst with a pronounced double-peaked structure in hard X-rays, reminiscent of the double-peaked temporal structure seen in some bright thermonuclear bursts on accreting neutron stars. In the latter case this is

  9. A theory of gamma-ray bursts

    NARCIS (Netherlands)

    Brown, G.E.; Lee, C.-H.; Wijers, R.A.M.J.; Lee, H.K.; Israelian, G.; Bethe, H.A.

    2000-01-01

    Recent observations and theoretical considerations have linked gamma-ray bursts with ultra-bright type Ibc supernovae (`hypernovae'). We here work out a specific scenario for this connection. Based on earlier work, we argue that especially the longest bursts must be powered by the Blandford-Znajek

  10. GRB060602B = Swift J1749.4−2807: an unusual transiently accreting neutron-star X-ray binary

    NARCIS (Netherlands)

    Wijnands, R.; Rol, E.; Cackett, E.; Starling, R.L.C.; Remillard, R.A.

    2009-01-01

    We present an analysis of the Swift Burst Alert Telescope (BAT) and X-ray telescope (XRT) data of GRB060602B, which is most likely an accreting neutron star in a binary system and not a gamma-ray burst. Our analysis shows that the BAT burst spectrum is consistent with a thermonuclear flash (type I

  11. Goddard Robotic Telescope - Optical Follow-up of GRBs and Coordinated Observations of AGNs

    Science.gov (United States)

    Sakamoto, T.; Wallace, C. A.; Donato, D.; Gehrels, N.; Okajima, T.; Ukwatta, T. N.

    2010-01-01

    Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur or when Active Galactic Nucleus (AGN) flaring activity starts, follow-up/monitoring ground telescopes must be located as uniformly as possible all over the world in order to collect data simultaneously with Fermi and Swift detections. However, there is a distinct gap in follow-up coverage of telescopes in the eastern U.S. region based on the operations of Swift. Motivated by this fact, we have constructed a 14" fully automated optical robotic telescope, Goddard Robotic Telescope (GRT), at the Goddard Geophysical and Astronomical Observatory. The aims of our robotic telescope are 1) to follow-up Swift/Fermi GRBs and 2) to perform the coordinated optical observations of Fermi Large Area Telescope (LAT) AGN. Our telescope system consists of off-the-shelf hardware. With the focal reducer, we are able to match the field of view of Swift narrow instruments (20' x 20'). We started scientific observations in mid-November 2008 and GRT has been fully remotely operated since August 2009. The 3(sigma) upper limit in a 30-second exposure in the R filter is approx.15.4 mag; however, we can reach to approx.18 mag in a 600-second exposures. Due to the weather condition at the telescope site. our observing efficiency is 30-40%, on average.

  12. The EXIST Infra-Red Telescope System: Design and Performance

    Science.gov (United States)

    Moseley, Harvey; Golisano, C.; Gong, Q.; Allen, B.; Grindlay, J.; Hong, J.; Kutyrev, A.; Woodgate, B.; EXIST Team

    2010-01-01

    The Infra-Red Telescope is a critical element of the EXIST (Energetic X-Ray Imaging Survey Telescope) observatory. It is a passively cooled 1.1m visible/infrared telescope. The primary goal of the IRT is to obtain photometric and spectroscopic measurements of high redshift (>6) gamma ray burst afterglows to study the nature of these enigmatic events and the their environments, and to use them as probes of the composition and ionization state of the intergalactiic medium of the young universe . The IRT will provide a prompt follow up (within three minutes) of the transient discovered by the EXIST with exceptional NIR sensitivitiy (AB=24 in 100s) surpassing HST in the infrared due to its passively cooled (-30ºC) mirror. Its optical design and spectral coverage is tailored to the high redshift transient events that require prompt pointing, identification, accurate phototmetry and both low and high resolution spectroscopy. Here we describe the telescope, its instrument complement, and the cooling systems which provide its remarkable sensitivity.

  13. The EXIST Infra-Red Telescope System: Design and Performance

    Science.gov (United States)

    Moseley, Samuel H.

    2010-01-01

    The Infra-Red Telescope is a critical element of the EXIST (Energetic X-Ray Imaging Survey Telescope) observatory. It is a passively cooled 1.lm visible/infrared telescope. The primary goal of the IRT is to obtain photometric and spectroscopic measurements of high redshift (>6) gamma ray burst afterglows to study the nature of these enigmatic events and their environments, and to use them as probes of the composition and ionization state of the intergalactic medium of the young universe. The IRT will provide a prompt follow up (within three minutes) of the transient discovered by the EXIST with exceptional NIR sensitivity (AB=24 in 100s) surpassing HST in the infrared due to its passively cooled (- 30 C) mirror. Its optical design and spectral coverage is tailored to the high redshift transient events that require prompt pointing, identification, accurate photometry and both low and high resolution spectroscopy. Here we describe the telescope, its instrument complement, and the cooling systems which provide its remarkable sensitivity

  14. Hubble Space Telescope STIS Observations of GRB 000301C: CCD Imaging and Near-Ultraviolet MAMA Spectroscopy

    NARCIS (Netherlands)

    Smette, A.; Fruchter, A.S.; Gull, Th.R.; Sahu, K.C.; Petro, L.; Ferguson, H.; Rhoads, J.; Lindler, D.J.; Wijers, R.A.M.J.

    2001-01-01

    We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the gamma-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R~=21.50+/-0.15 source with no apparent host galaxy. An 8000 s, 1150

  15. Hubble Space Telescope STIS observations of GRB 000301C: CCD imaging and near-ultraviolet MAMA spectroscopy

    DEFF Research Database (Denmark)

    Smette, A.; Fruchter, A.S.; Gull, T.R.

    2001-01-01

    We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the c-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R similar or equal to 21.50 +/- 0.15 source with no apparent host galaxy. ...

  16. The effect of automated alerts on preoperative anemia management.

    Science.gov (United States)

    Dilla, Andrew; Wisniewski, Mary Kay; Waters, Jonathan H; Triulzi, Darrell J; Yazer, Mark H

    2015-04-01

    This study evaluated the role of an automated anemia notification system that alerted providers about anemic pre-operative patients. After scheduling surgery, the alert program continuously searched the patient's laboratory data for hemoglobin value(s) in the medical record. When an anemic patient according to the World Health Oganization's criteria was identified, an email was sent to the patient's surgeon, and/or assistant, and/or patient's primary care physician suggesting that the anemia be managed before surgery. Thirteen surgeons participated in this pilot study. In 11 months, there were 70 pre-surgery anemia alerts generated on 69 patients. The surgeries were 60 orthopedic, 7 thoracic, 2 general surgery, and 1 urological. The alerts were sent 15 ± 10 days before surgery. No pre-operative anemia treatment could be found in 37 of 69 (54%) patients. Some form of anemia management was found in 32 of 69 (46%) patients. Of the 23 patients who received iron, only 3 of 23 (13%) of these patients started iron shortly after the alert was generated. The alert likely resulted in the postponement of one surgery for anemia correction. Although anemia diagnosis and management can be complex, it was hoped that receipt of the alert would lead to the management of all anemic patients. Alerts are only effective if they are received and read by a healthcare provider empowered to treat the patient or to make an appropriate referral. Automated preoperative alerts alone are not likely to alter surgeons' anemia management practices. These alerts need to be part of a comprehensive anemia management strategy.

  17. The Planck Telescope reflectors

    Science.gov (United States)

    Stute, Thomas

    2004-09-01

    The mechanical division of EADS-Astrium GmbH, Friedrichshafen is currently engaged with the development, manufacturing and testing of the advanced dimensionally stable composite reflectors for the ESA satellite borne telescope Planck. The objective of the ESA mission Planck is to analyse the first light that filled the universe, the cosmic microwave background radiation. Under contract of the Danish Space Research Institute and ESA EADS-Astrium GmbH is developing the all CFRP primary and secondary reflectors for the 1.5-metre telescope which is the main instrument of the Planck satellite. The operational frequency ranges from to 25 GHz to 1000 GHz. The demanding high contour accuracy and surface roughness requirements are met. The design provides the extreme dimensional stability required by the cryogenic operational environment at around 40 K. The elliptical off-axis reflectors display a classical lightweight sandwich design with CFRP core and facesheets. Isostatic mounts provide the interfaces to the telescope structure. Protected VDA provides the reflecting surface. The manufacturing is performed at the Friedrichshafen premises of EADS-Space Transportation GmbH, the former Dornier composite workshops. Advanced manufacturing technologies like true angle lay-up by CNC fibre placement and filament winding are utilized. The protected coating is applied at the CAHA facilities at the Calar Alto Observatory, Spain. The exhaustive environmental testing is performed at the facilities of IABG, Munich (mechanical testing) and for the cryo-optical tests at CSL Liege. The project is in advanced state with both Qualification Models being under environmental testing. The flight models will be delivered in 2004. The paper gives an overview over the requirements and the main structural features how these requirements are met. Special production aspects and available test results are reported.

  18. Is Your Telescope Tweeting?

    Science.gov (United States)

    Atkinson, Nancy

    2009-05-01

    Half of the world's population today was born after the Apollo Moon landings. The best way to reach this generation and get them excited about today's space exploration and astronomy news and events is through online social media, which are technologies that allow anyone to communicate with everyone. Twitter is a growing popular social media tool that uses short, 140 character "Tweets" to quickly and concisely convey updates on what you "are doing." With the right combination of information, personality and fun, telescopes and spacecraft are using Twitter for public outreach, providing important status updates while making the public feel like they are part of the mission.

  19. Integrating Medication Alert Data into a Clinical Data Repository to Enable Retrospective Study of Drug Interaction Alerts in Clinical Practice.

    Science.gov (United States)

    Liu, Mei; Melton, Brittany L; Ator, Gregory; Waitman, Lemuel R

    2017-01-01

    Current clinical data repositories primarily extract data from multiple administrative and electronic medical record (EMR) data resources (e.g., hospital and physician billing records) containing specific patient-level data including demographics, medications, laboratory results, diagnoses, and procedure codes. It overlooks the importance of EMR system-level data (e.g., medication alerts that are routinely used by physicians, nurses, and pharmacists for decision support) for the surveillance of EMR decision support tools. These medication alerts are a significant source of information for providers, to minimize avoidable adverse drug events. This study describes the integration of medication alert data into an i2b2-based clinical data repository to support the investigation of clinical events occurring around patients with anticoagulation treatment that triggered drug-drug interaction alerts. The integration of medication alerts allows us to repurpose the clinical and translational research infrastructure to conduct retrospective effectiveness surveillance of clinical decision support tools.

  20. A Repeating Fast Radio Burst: Radio and X-ray Follow-up Observations of FRB 121102

    Science.gov (United States)

    Scholz, Paul; Spitler, Laura; Hessels, Jason; Bogdanov, Slavko; Brazier, Adam; Camilo, Fernando; Chatterjee, Shami; Cordes, James M.; Crawford, Fronefield; Deneva, Julia S.; Ferdman, Robert; Freire, Paulo; Kaspi, Victoria M.; Lazarus, Patrick; Lynch, Ryan; Madsen, Erik; McLaughlin, Maura; Patel, Chitrang; Ransom, Scott M.; Seymour, Andrew; Stairs, Ingrid H.; Stappers, Benjamin; van Leeuwen, Joeri; Zhu, Weiwei

    2016-04-01

    A new phenomenon has emerged in high-energy astronomy in the past few years: the Fast Radio Burst. Fast Radio Bursts (FRBs) are millisecond-duration radio bursts whose dispersion measures imply that they originate from far outside of the Galaxy. Their origin is as yet unknown; their durations and energetics imply that they involve compact objects, such as neutron stars or black holes. Due to their extreme luminosities implied by their distances and the previous absence of any repeat burst in follow-up observations, many potential explanations involve one-time cataclysmic events. However, in our Arecibo telescope follow-up observations of FRB 121102 (discovered in the PALFA survey; Spitler et al. 2014), we find additional bursts at the same location and dispersion measure as the original burst. We also present the results of Swift and Chandra X-ray observations of the field. This result shows that, for at least a sub-set of the FRB population, the source can repeat and thus cannot be explained by a cataclysmic origin.

  1. Machine Learning-based Transient Brokers for Real-time Classification of the LSST Alert Stream

    Science.gov (United States)

    Narayan, Gautham; Zaidi, Tayeb; Soraisam, Monika; ANTARES Collaboration

    2018-01-01

    The number of transient events discovered by wide-field time-domain surveys already far outstrips the combined followup resources of the astronomical community. This number will only increase as we progress towards the commissioning of the Large Synoptic Survey Telescope (LSST), breaking the community's current followup paradigm. Transient brokers - software to sift through, characterize, annotate and prioritize events for followup - will be a critical tool for managing alert streams in the LSST era. Developing the algorithms that underlie the brokers, and obtaining simulated LSST-like datasets prior to LSST commissioning, to train and test these algorithms are formidable, though not insurmountable challenges. The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is a joint project of the National Optical Astronomy Observatory and the Department of Computer Science at the University of Arizona. We have been developing completely automated methods to characterize and classify variable and transient events from their multiband optical photometry. We describe the hierarchical ensemble machine learning algorithm we are developing, and test its performance on sparse, unevenly sampled, heteroskedastic data from various existing observational campaigns, as well as our progress towards incorporating these into a real-time event broker working on live alert streams from time-domain surveys.

  2. Polaris Tracking Telescope

    Science.gov (United States)

    Ritchie, Justin; Castelaz, M.; Cline, D. J.

    2009-01-01

    Pisgah Astronomical Research Institute (PARI) in Rosman, NC has been imaging 5 degrees of the sky surrounding Polaris since 2004 using a wide-angle lens and CCD camera. The images are used for differential photometry and to measure the variation in brightness of the Polaris itself. To enhance the quality of the measurements of Polaris a special robotic telescope mount was built to accommodate a narrow field-of-view telescope that focuses on Polaris alone. The movement of Polaris is a circle about 1 degree in radius every 24 hours which is 1 arcsecond every 8 seconds of clock time. The design team had to consider that the polar axis is on a 19-year cycle due to the changing lunar gravitational attractions upon the earth's equatorial bulge. There are several components to this effect. The lunar component amplitude is +/-9 arcseconds towards the ecliptic pole with a period of 18.6 years. The solar component is +/- 1.2 arcseconds over 0.5 years; there is a 'fortnightly nutation' of +/- 0.1 arcseconds per 5 days; there is also a seasonal variation caused by the movement of airm asses of +/- 0.18 arcseconds per year. Utilizing two CCD cameras, the SBIG STV and the SBIG ST7 we can capture the image of Polaris by following the path of the star in the sky with linear actuators set to the coordinates of its circular path.

  3. Magellan Telescopes operations 2008

    Science.gov (United States)

    Osip, David J.; Phillips, Mark M.; Palunas, Povilas; Perez, Frank; Leroy, M.

    2008-07-01

    The twin 6.5m Magellan Telescopes have been in routine operations at the Las Campanas Observatory in the Chilean Andes since 2001 and 2002 respectively. The telescopes are owned and operated by Carnegie for the benefit of the Magellan consortium members (Carnegie Institution of Washington, Harvard University, the University of Arizona, Massachusetts Institute of Technology, and the University of Michigan). This paper provides an up to date review of the scientific, technical, and administrative structure of the 'Magellan Model' for observatory operations. With a modest operations budget and a reasonably small staff, the observatory is operated in the "classical" mode, wherein the visiting observer is a key member of the operations team. Under this model, all instrumentation is supplied entirely by the consortium members and the various instrument teams continue to play a critical support role beyond initial deployment and commissioning activities. Here, we present a critical analysis of the Magellan operations model and suggest lessons learned and changes implemented as we continue to evolve an organizational structure that can efficiently deliver a high scientific return for the investment of the partners.

  4. Origins Space Telescope

    Science.gov (United States)

    Cooray, Asantha; Origins Space Telescope Study Team

    2018-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. This presentation will provide a summary of the OST STDT, our completed first mission concept and an introduction to the second concept that will be studied at the study center in 2018. This presentation will also summarize key science drivers and the key study milestones between 2018 and 2020.

  5. Deep space telescopes

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo’s telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics throughout the complete electromagnetic spectrum. Such information is there for the taking, from millimiter wavelengths to gamma rays. Forty years astronomy from space, covering now most of the e.m. spectrum, have thus given us a better understanding of our physical Universe then t...

  6. Spitzer ToO observations of a short gamma-ray burst

    Science.gov (United States)

    Hurley, Kevin; Bloom, Joshua; Butler, Nathaniel; Falco, Emilio; Foley, Ryan; Granot, Jonathan; Kocevski, Daniel; Lee, William; Li, Weidong; Mahoney, William; Pahre, Michael; Panaitescu, Alin; Perley, Daniel; Prochaska, Jason; Ramirez-Ruiz, Enrico; Smith, Ian; Squires, Gordon

    2008-03-01

    An understanding of the origin of the short gamma-ray bursts remains an elusive and exciting pursuit. A great leap forward has been made over the past three years with the first rapid localizations and afterglow detections of such events, but follow-up has yet to reveal a detailed understanding of the progenitors and the nature of the afterglow light. We propose an ambitious multiwavelength approach to the problem, leveraging Spitzer with Chandra as well as numerous ground-based telescopes. By measuring the broad-band spectrum of the afterglow and any concurrent 'mini-supernova ' over a wide range of wavelengths at several epochs, we can distinguish between models proposed to explain this type of burst. We will constrain the energetics of the explosion and the short GRB bursting rate (an important number for gravitational wave observatories), and measure with unprecedented detail the stellar content of a short burst host galaxy. Given the high impact nature of these observations and the rarity of short bursts, we are requesting multiepoch Target of Opportunity observations on a single event in Cycle 5. The wavelengths observed by Spitzer, when used in coordination with these other instruments, can make a crucial contribution to understanding the nature of short duration GRBs, particularly by removing the degeneracies among the models due to dust extinction. This is a resubmission of our AO-4 ToO proposal, which has not been called yet. However, even if that observation is carried out, we are requesting an AO-5 observation, because so little is known about the short bursts that each new detection adds a very significant amount of information. Harvey Tananbaum has agreed to grant us Chandra ToO time through November 2008 (the end of Chandra AO-9) if Spitzer observations are carried out. Following that, we will submit a Chandra AO-10 proposal for ToO time; if warranted, we will request Chandra Director's Discretionary Time to support our Spitzer observations.

  7. Why Space Telescopes Are Amazing

    Science.gov (United States)

    Rigby, Jane R.

    2012-01-01

    One of humanity's best ideas has been to put telescopes in space. The dark stillness of space allows telescopes to perform much better than they can on even the darkest and clearest of Earth's mountaintops. In addition, from space we can detect colors of light, like X-rays and gamma rays, that are blocked by the Earth's atmosphere I'll talk about NASA's team of great observatories: the Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory} and how they've worked together to answer key questions: When did the stars form? Is there really dark matter? Is the universe really expanding ever faster and faster?

  8. Perceptual evaluation of visual alerts in surveillance videos

    Science.gov (United States)

    Rogowitz, Bernice E.; Topkara, Mercan; Pfeiffer, William; Hampapur, Arun

    2015-03-01

    Visual alerts are commonly used in video monitoring and surveillance systems to mark events, presumably making them more salient to human observers. Surprisingly, the effectiveness of computer-generated alerts in improving human performance has not been widely studied. To address this gap, we have developed a tool for simulating different alert parameters in a realistic visual monitoring situation, and have measured human detection performance under conditions that emulated different set-points in a surveillance algorithm. In the High-Sensitivity condition, the simulated alerts identified 100% of the events with many false alarms. In the Lower-Sensitivity condition, the simulated alerts correctly identified 70% of the targets, with fewer false alarms. In the control condition, no simulated alerts were provided. To explore the effects of learning, subjects performed these tasks in three sessions, on separate days, in a counterbalanced, within subject design. We explore these results within the context of cognitive models of human attention and learning. We found that human observers were more likely to respond to events when marked by a visual alert. Learning played a major role in the two alert conditions. In the first session, observers generated almost twice as many False Alarms as in the No-Alert condition, as the observers responded pre-attentively to the computer-generated false alarms. However, this rate dropped equally dramatically in later sessions, as observers learned to discount the false cues. Highest observer Precision, Hits/(Hits + False Alarms), was achieved in the High Sensitivity condition, but only after training. The successful evaluation of surveillance systems depends on understanding human attention and performance.

  9. Observational properties of decameter type IV bursts

    Science.gov (United States)

    Melnik, Valentin; Brazhenko, Anatoly; Rucker, Helmut; Konovalenko, Alexander; Briand, Carine; Dorovskyy, Vladimir; Zarka, Philippe; Frantzusenko, Anatoly; Panchenko, Michael; Poedts, Stefan; Zaqarashvili, Teimuraz; Shergelashvili, Bidzina

    2013-04-01

    Oscillations of decameter type IV bursts were registered during observations of solar radio emission by UTR-2, URAN-2 and NDA in 2011-2012. Large majority of these bursts were accompanied by coronal mass ejections (CMEs), which were observed by SOHO and STEREO in the visible light. Only in some cases decameter type IV bursts were not associated with CMEs. The largest periods of oscillations P were some tens of minutes. There were some modes of long periods of oscillations simultaneously. Periods of oscillations in flux and in polarization profiles were close. Detailed properties of oscillations at different frequencies were analyzed on the example of two type IV bursts. One of them was observed on April 7, 2011 when a CME happened. Another one (August 1, 2011) was registered without any CME. The 7 April type IV burst had two periods in the frames 75-85 and 35-85 minutes. Interesting feature of these oscillations is decreasing periods with time. The observed decreasing rates dP/dt equaled 0.03-0.07. Concerning type IV burst observed on August 1, 2011 the period of its oscillations increases from 17 min. at 30 MHz to 44 min. at 10 MHz. Connection of type IV burst oscillations with oscillations of magnetic arches and CMEs at corresponding altitudes are discussed. The work is fulfilled in the frame of FP7 project "SOLSPANET".

  10. Bursting neurons and ultrasound avoidance in crickets

    Directory of Open Access Journals (Sweden)

    Gary eMarsat

    2012-07-01

    Full Text Available Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes –bursts– that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing –the auditory receptor- already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2’s sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.

  11. Burst Oscillations: Watching Neutron Stars Spin

    Science.gov (United States)

    Strohmayer, Tod

    2010-01-01

    It is now almost 15 years since the first detection of rotationally modulated emission from X-ray bursting neutron stars, "burst oscillations," This phenomenon enables us to see neutron stars spin, as the X-ray burst flux asymmetrically lights up the surface. It has enabled a new way to probe the neutron star spin frequency distribution, as well as to elucidate the multidimensional nature of nuclear burning on neutron stars. I will review our current observational understanding of the phenomenon, with an eye toward highlighting some of the interesting remaining puzzles, of which there is no shortage.

  12. Limits on neutrino emission from gamma-ray bursts with the 40 string IceCube detector.

    Science.gov (United States)

    Abbasi, R; Abdou, Y; Abu-Zayyad, T; Adams, J; Aguilar, J A; Ahlers, M; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Bazo Alba, J L; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K-H; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bose, D; Böser, S; Botner, O; Braun, J; Brown, A M; Buitink, S; Carson, M; Chirkin, D; Christy, B; Clem, J; Clevermann, F; Cohen, S; Colnard, C; Cowen, D F; D'Agostino, M V; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; Demirörs, L; Depaepe, O; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Díaz-Vélez, J C; Dierckxsens, M; Dreyer, J; Dumm, J P; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegård, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Geisler, M; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Goodman, J A; Grant, D; Griesel, T; Gross, A; Grullon, S; Gurtner, M; Ha, C; Hallgren, A; Halzen, F; Han, K; Hanson, K; Heinen, D; Helbing, K; Herquet, P; Hickford, S; Hill, G C; Hoffman, K D; Homeier, A; Hoshina, K; Hubert, D; Huelsnitz, W; Hülss, J-P; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K-H; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kemming, N; Kenny, P; Kiryluk, J; Kislat, F; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, S; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Krings, T; Kroll, G; Kuehn, K; Kuwabara, T; Labare, M; Lafebre, S; Laihem, K; Landsman, H; Larson, M J; Lauer, R; Lehmann, R; Lünemann, J; Madsen, J; Majumdar, P; Marotta, A; Maruyama, R; Mase, K; Matis, H S; Meagher, K; Merck, M; Mészáros, P; Meures, T; Middell, E; Milke, N; Miller, J; Montaruli, T; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Niessen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Ono, M; Panknin, S; Paul, L; Pérez de los Heros, C; Petrovic, J; Piegsa, A; Pieloth, D; Porrata, R; Posselt, J; Price, P B; Prikockis, M; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Rodrigues, J P; Roth, P; Rothmaier, F; Rott, C; Ruhe, T; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Schmidt, T; Schoenwald, A; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Slipak, A; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stephens, G; Stezelberger, T; Stokstad, R G; Stoyanov, S; Strahler, E A; Straszheim, T; Sullivan, G W; Swillens, Q; Taavola, H; Taboada, I; Tamburro, A; Tarasova, O; Tepe, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Tosi, D; Turčan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Voigt, B; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Weaver, C; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wischnewski, R; Wissing, H; Wolf, M; Woschnagg, K; Xu, C; Xu, X W; Yodh, G; Yoshida, S; Zarzhitsky, P

    2011-04-08

    IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18)  eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.

  13. The metagenomic telescope.

    Directory of Open Access Journals (Sweden)

    Balázs Szalkai

    Full Text Available Next generation sequencing technologies led to the discovery of numerous new microbe species in diverse environmental samples. Some of the new species contain genes never encountered before. Some of these genes encode proteins with novel functions, and some of these genes encode proteins that perform some well-known function in a novel way. A tool, named the Metagenomic Telescope, is described here that applies artificial intelligence methods, and seems to be capable of identifying new protein functions even in the well-studied model organisms. As a proof-of-principle demonstration of the Metagenomic Telescope, we considered DNA repair enzymes in the present work. First we identified proteins in DNA repair in well-known organisms (i.e., proteins in base excision repair, nucleotide excision repair, mismatch repair and DNA break repair; next we applied multiple alignments and then built hidden Markov profiles for each protein separately, across well-researched organisms; next, using public depositories of metagenomes, originating from extreme environments, we identified DNA repair genes in the samples. While the phylogenetic classification of the metagenomic samples are not typically available, we hypothesized that some very special DNA repair strategies need to be applied in bacteria and Archaea living in those extreme circumstances. It is a difficult task to evaluate the results obtained from mostly unknown species; therefore we applied again the hidden Markov profiling: for the identified DNA repair genes in the extreme metagenomes, we prepared new hidden Markov profiles (for each genes separately, subsequent to a cluster analysis; and we searched for similarities to those profiles in model organisms. We have found well known DNA repair proteins, numerous proteins with unknown functions, and also proteins with known, but different functions in the model organisms.

  14. Wide-Field Imaging Telescope-0 (WIT0) with automatic observing system

    Science.gov (United States)

    Ji, Tae-Geun; Byeon, Seoyeon; Lee, Hye-In; Park, Woojin; Lee, Sang-Yun; Hwang, Sungyong; Choi, Changsu; Gibson, Coyne Andrew; Kuehne, John W.; Prochaska, Travis; Marshall, Jennifer L.; Im, Myungshin; Pak, Soojong

    2018-01-01

    We introduce Wide-Field Imaging Telescope-0 (WIT0), with an automatic observing system. It is developed for monitoring the variabilities of many sources at a time, e.g. young stellar objects and active galactic nuclei. It can also find the locations of transient sources such as a supernova or gamma-ray bursts. In 2017 February, we installed the wide-field 10-inch telescope (Takahashi CCA-250) as a piggyback system on the 30-inch telescope at the McDonald Observatory in Texas, US. The 10-inch telescope has a 2.35 × 2.35 deg field-of-view with a 4k × 4k CCD Camera (FLI ML16803). To improve the observational efficiency of the system, we developed a new automatic observing software, KAOS30 (KHU Automatic Observing Software for McDonald 30-inch telescope), which was developed by Visual C++ on the basis of a windows operating system. The software consists of four control packages: the Telescope Control Package (TCP), the Data Acquisition Package (DAP), the Auto Focus Package (AFP), and the Script Mode Package (SMP). Since it also supports the instruments that are using the ASCOM driver, the additional hardware installations become quite simplified. We commissioned KAOS30 in 2017 August and are in the process of testing. Based on the WIT0 experiences, we will extend KAOS30 to control multiple telescopes in future projects.

  15. Infrared up-conversion telescope

    DEFF Research Database (Denmark)

    2014-01-01

    There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...

  16. Kashima 34-m Radio Telescope

    Science.gov (United States)

    Sekido, Mamoru; Kawai, Eiji

    2013-01-01

    The Kashima 34-m radio telescope has been continuously operated and maintained by the National Institute of Information and Communications Technology (NICT) as a facility of the Kashima Space Technology Center (KSTC) in Japan. This brief report summarizes the status of this telescope, the staff, and activities during 2012.

  17. On Gamma-Ray Bursts

    CERN Document Server

    Ruffini, Remo; Bianco, Carlo Luciano; Caito, Letizia; Chardonnet, Pascal; Cherubini, Christian; Dainotti, Maria Giovanna; Fraschetti, Federico; Geralico, Andrea; Guida, Roberto; Patricelli, Barbara; Rotondo, Michael; Hernandez, Jorge Armando Rueda; Vereshchagin, Gregory; Xue, She-Sheng

    2008-01-01

    (Shortened) We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the...

  18. Office of Child Support and Enforcement (OCSE) State Wage Alerts

    Data.gov (United States)

    Social Security Administration — The OCSE State Wage Alert is a quarterly match which detects SSI overpayments by identifying unreported wage and unemployment data provided to the Office of Child...

  19. Real-Time Alerts and Reminders Using Information Systems

    Science.gov (United States)

    Sandberg, Warren S; Ehrenfeld, Jesse M

    2011-01-01

    Synopsis Adoption of information systems throughout the hospital environment has enabled the development of real-time physiologic alerts and clinician reminder systems. Within the operating room environment, these clinical tools can be made available through the deployment of anesthesia information management systems (AIMS). Creating usable alert systems requires understanding technical considerations including system latency, workflow integration and the availability of appropriate alerting technology. A variety of successful implementations are reviewed, encompass cost reduction, improved revenue capture, timely antibiotic administration and post-op nausea and vomiting prophylaxis. Challenges to the widespread use of real-time alerts and reminders include AIMS adoption rates and the difficulty in appropriately choosing areas and approaches for information systems support. PMID:21871401

  20. Siren system installed to alert campus community to emergency events

    OpenAIRE

    Miller, Allan

    2006-01-01

    Virginia Tech is installing a system of warning sirens to alert the campus community to emergency events. The first test of the siren system is scheduled to occur on Wednesday, April 19, at 12:10 p.m.

  1. Algorthms and Regolith Erosion Models for the Alert Code Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC and Duke University have teamed on this STTR to develop the ALERT (Advanced Lunar Exhaust-Regolith Transport) code which will include new developments in...

  2. Chemical Safety Alert: Hazards of Delayed Coker Unit (DCU) Operations

    Science.gov (United States)

    EPA and OSHA jointly publish this Chemical Safety Alert/Safety and Health Information Bulletin (CSA/SHIB) to increase awareness. DCU is a severe form of thermal cracking requiring high temperatures for long periods, for refining crude oils.

  3. ALERTES EEWS for South Iberia: feasibility and prototype

    Science.gov (United States)

    Pazos, Antonio; Romeu, Nuria; Lozano, Lucia; Colom, Yolanda; López Mesa, Mireya; Goula, Xavier; Jara, Jose Antonio; Cantavella, Jose Vicente; Davila, Jose Martin; Zollo, Aldo; Hanka, Winfried; Carrilho, Fernando; Carranza, Marta; Buforn, Elisa; Civeria, Angel; Rioja, Carlos; Morgado, Arturo

    2015-04-01

    The Spanish ALERT-ES project was set up to study the feasibility of setting up an Earthquake Early Warning System to warn the potentially damaging earthquakes that can occur in the SW of Iberia peninsula, such as the 1755 Lisbon earthquake. Four events, located close to the epicentres of the largest earthquakes in the area, were simulated and the errors were analyzed. In addition, a study about the blind zone and the lead time at six selected targets was carried out. The results show a blind zone in the SW corner of Portugal for SV earthquakes and also a blind zone in the coastal area, from Portimao to Cadiz, for the GC earthquakes. Currently, an EEWS prototype, called ALERTES system, based on SeisComP3 software, is running on cuasi-real time under test for Ibero-Magrhebian region, in the frame of the ALERTES-RIM Spanish project.

  4. Participatory design for drug-drug interaction alerts.

    Science.gov (United States)

    Luna, Daniel; Otero, Carlos; Almerares, Alfredo; Stanziola, Enrique; Risk, Marcelo; González Bernaldo de Quirós, Fernán

    2015-01-01

    The utilization of decision support systems, in the point of care, to alert drug-drug interactions has been shown to improve quality of care. Still, the use of these systems has not been as expected, it is believed, because of the difficulties in their knowledge databases; errors in the generation of the alerts and the lack of a suitable design. This study expands on the development of alerts using participatory design techniques based on user centered design process. This work was undertaken in three stages (inquiry, participatory design and usability testing) it showed that the use of these techniques improves satisfaction, effectiveness and efficiency in an alert system for drug-drug interactions, a fact that was evident in specific situations such as the decrease of errors to meet the specified task, the time, the workload optimization and users overall satisfaction in the system.

  5. Long Burst Error Correcting Codes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long burst error mitigation is an enabling technology for the use of Ka band for high rate commercial and government users. Multiple NASA, government, and commercial...

  6. POPULATION SYNTHESIS AND GAMMA RAY BURST PROGENITORS

    Energy Technology Data Exchange (ETDEWEB)

    C. L. FREYER

    2000-12-11

    Population synthesis studies of binaries are always limited by a myriad of uncertainties from the poorly understood effects of binary mass transfer and common envelope evolution to the many uncertainties that still remain in stellar evolution. But the importance of these uncertainties depends both upon the objects being studied and the questions asked about these objects. Here I review the most critical uncertainties in the population synthesis of gamma-ray burst progenitors. With a better understanding of these uncertainties, binary population synthesis can become a powerful tool in understanding, and constraining, gamma-ray burst models. In turn, as gamma-ray bursts become more important as cosmological probes, binary population synthesis of gamma-ray burst progenitors becomes an important tool in cosmology.

  7. [Usability of smartphones for dose alerts].

    Science.gov (United States)

    Kaireit, T; Stamm, G; Hoeschen, C; Wacker, F K

    2013-06-01

    Smartphone apps for measuring ionizing radiation use the capability of (CMOS) camera chips to detect not only perceivable light but also electromagnetic wave radiation. The present study evaluates the accuracy of hardware and software and defines possible applications for the detection of X-ray radiation fields. 2 apps and 2 different devices were tested in comparison with a calibrated ionization chamber and a personal electronic dosimeter. A calibration curve was determined for dose rates between 12 700 µSv/h and 5.7 µSv/h generated by a C-arm system. The measured scattered radiation produced by an Alderson-Rando phantom ranged from 117 µSv/h (at a distance of 2 m) to 5910 µSv/h (at a distance of 0.3 m) and was 1.4 times less than the values of the ionization chamber. The exposure rate for the operator's thyroid was within 4200 - 4400 µSv/h. We found a strong dependence of the measurements on the angulation of the Smartphone, especially for short distances from the phantom (at a distance of 0.3 m, a 45° rotation downwards in a vertical direction caused a decrease from 3000 µSv/h to 972 µSv/h, while an upwards rotation resulted in an increase to 5000 µSv/h). For a distance of 1 m, this effect was remarkably smaller. Smartphones can be used to detect ionizing radiation but showed limited accuracy and are heavily dependent on the angulation of the device. Qualitative measurements and utilization for dose alerts are possible. © Georg Thieme Verlag KG Stuttgart · New York.

  8. The Seismic Alert System of Mexico (SASMEX): Performance and Evolution

    Science.gov (United States)

    Espinosa Aranda, J.

    2013-05-01

    Originally the Seismic Alert System of Mexico (SASMEX) was proposed to integrate the Seismic Alert System of Mexico City (SAS), operating since 1991, with the Seismic Alert System of Oaxaca City (SASO), in services since 2003. And today, after the intense big earthquake activity observed in our world during 2010 and 2011, local governments of Mexico City, Oaxaca Estate, and the Mexican Ministry of the Interior have been promoting the expansion of this technological EEW development. Until 2012 SASMEX better coverage includes 48 new field seismic sensors (FS) deployed over the seismic region of Jalisco, Colima, Michoacan and Puebla, with someone enhancements over Guerrero and Oaxaca, to reach 97 FS. During 2013, 35 new FS has been proposed to SASMEX enhancements covering the Chiapas and Veracruz seismic regions. The SASMEX, with the support of the Mexico Valley Broadcasters Association (ARVM) since 1993, automatically issue Public and Preventive earthquake early warning signals in the Cities of Mexico, Toluca, Acapulco, Chilpancingo, and Oaxaca. The seismic warning range in each case is seated in accordance with local Civil Protection Authorities: Public Alert, if they expect strong earthquake effects, and Preventive Alert one, the effect could be moderated. Now the SASMEX warning time opportunity could be different to the 60 sec. average typically generated when SAS warned earthquake effects coming from Guerrero to Mexico City valley. Mexican EEW issued today reach: 16 Public and 62 Preventive Alert in Mexico City; 25 Public and 19 Preventive Alerts in Oaxaca City; also 14 Public and 4 Preventive Alerts in Acapulco; 14 Public and 5 Preventive Alerts in Chilpancingo. The earthquakes events registered by SASMEX FS until now reach 3448. With the support of private and Federal telecommunications infrastructure like, TELMEX, Federal Electric Commission, and the Mexican Security Ministry, it was developed a redundant communication system with pads to link the different

  9. Testing Brans-Dicke gravity using the Einstein telescope

    Science.gov (United States)

    Zhang, Xing; Yu, Jiming; Liu, Tan; Zhao, Wen; Wang, Anzhong

    2017-06-01

    Gravitational radiation is an excellent field for testing theories of gravity in strong gravitational fields. The current observations on the gravitational-wave (GW) bursts by LIGO have already placed various constraints on the alternative theories of gravity. In this paper, we investigate the possible bounds which could be placed on the Brans-Dicke gravity using GW detection from inspiraling compact binaries with the proposed Einstein Telescope, a third-generation GW detector. We first calculate in detail the waveforms of gravitational radiation in the lowest post-Newtonian approximation, including the tensor and scalar fields, which can be divided into the three polarization modes, i.e., "plus mode," "cross mode," and "breathing mode." Applying the stationary phase approximation, we obtain their Fourier transforms, and derive the correction terms in amplitude, phase, and polarization of GWs, relative to the corresponding results in general relativity. Imposing the noise level of the Einstein Telescope, we find that the GW detection from inspiraling compact binaries, composed of a neutron star and a black hole, can place stringent constraints on the Brans-Dicke gravity. The bound on the coupling constant ωBD depends on the mass, sky position, inclination angle, polarization angle, luminosity distance, redshift distribution, and total observed number NGW of the binary systems. Taking into account all the burst events up to redshift z =5 , we find that the bound could be ωBD≳1 06×(NGW/1 04)1/2. Even for the conservative estimation with 1 04 observed events, the bound is still more than one order tighter than the current limit from Solar System experiments. So, we conclude that the Einstein Telescope will provide a powerful platform to test alternative theories of gravity.

  10. Optimal Codes for the Burst Erasure Channel

    Science.gov (United States)

    Hamkins, Jon

    2010-01-01

    Deep space communications over noisy channels lead to certain packets that are not decodable. These packets leave gaps, or bursts of erasures, in the data stream. Burst erasure correcting codes overcome this problem. These are forward erasure correcting codes that allow one to recover the missing gaps of data. Much of the recent work on this topic concentrated on Low-Density Parity-Check (LDPC) codes. These are more complicated to encode and decode than Single Parity Check (SPC) codes or Reed-Solomon (RS) codes, and so far have not been able to achieve the theoretical limit for burst erasure protection. A block interleaved maximum distance separable (MDS) code (e.g., an SPC or RS code) offers near-optimal burst erasure protection, in the sense that no other scheme of equal total transmission length and code rate could improve the guaranteed correctible burst erasure length by more than one symbol. The optimality does not depend on the length of the code, i.e., a short MDS code block interleaved to a given length would perform as well as a longer MDS code interleaved to the same overall length. As a result, this approach offers lower decoding complexity with better burst erasure protection compared to other recent designs for the burst erasure channel (e.g., LDPC codes). A limitation of the design is its lack of robustness to channels that have impairments other than burst erasures (e.g., additive white Gaussian noise), making its application best suited for correcting data erasures in layers above the physical layer. The efficiency of a burst erasure code is the length of its burst erasure correction capability divided by the theoretical upper limit on this length. The inefficiency is one minus the efficiency. The illustration compares the inefficiency of interleaved RS codes to Quasi-Cyclic (QC) LDPC codes, Euclidean Geometry (EG) LDPC codes, extended Irregular Repeat Accumulate (eIRA) codes, array codes, and random LDPC codes previously proposed for burst erasure

  11. Alert management for home healthcare based on home automation analysis.

    Science.gov (United States)

    Truong, T T; de Lamotte, F; Diguet, J-Ph; Said-Hocine, F

    2010-01-01

    Rising healthcare for elder and disabled people can be controlled by offering people autonomy at home by means of information technology. In this paper, we present an original and sensorless alert management solution which performs multimedia and home automation service discrimination and extracts highly regular home activities as sensors for alert management. The results of simulation data, based on real context, allow us to evaluate our approach before application to real data.

  12. Monitoring alert and drowsy states by modeling EEG source nonstationarity

    Science.gov (United States)

    Hsu, Sheng-Hsiou; Jung, Tzyy-Ping

    2017-10-01

    Objective. As a human brain performs various cognitive functions within ever-changing environments, states of the brain characterized by recorded brain activities such as electroencephalogram (EEG) are inevitably nonstationary. The challenges of analyzing the nonstationary EEG signals include finding neurocognitive sources that underlie different brain states and using EEG data to quantitatively assess the state changes. Approach. This study hypothesizes that brain activities under different states, e.g. levels of alertness, can be modeled as distinct compositions of statistically independent sources using independent component analysis (ICA). This study presents a framework to quantitatively assess the EEG source nonstationarity and estimate levels of alertness. The framework was tested against EEG data collected from 10 subjects performing a sustained-attention task in a driving simulator. Main results. Empirical results illustrate that EEG signals under alert versus drowsy states, indexed by reaction speeds to driving challenges, can be characterized by distinct ICA models. By quantifying the goodness-of-fit of each ICA model to the EEG data using the model deviation index (MDI), we found that MDIs were significantly correlated with the reaction speeds (r  =  ‑0.390 with alertness models and r  =  0.449 with drowsiness models) and the opposite correlations indicated that the two models accounted for sources in the alert and drowsy states, respectively. Based on the observed source nonstationarity, this study also proposes an online framework using a subject-specific ICA model trained with an initial (alert) state to track the level of alertness. For classification of alert against drowsy states, the proposed online framework achieved an averaged area-under-curve of 0.745 and compared favorably with a classic power-based approach. Significance. This ICA-based framework provides a new way to study changes of brain states and can be applied to

  13. On the Prospects of Gamma-Ray Burst Detection in the TeV Band

    Science.gov (United States)

    Vurm, Indrek; Beloborodov, Andrei M.

    2017-09-01

    A gamma-ray burst (GRB) jet running into an external medium is expected to generate luminous GeV-TeV emission lasting from minutes to several hours. The high-energy emission results from inverse Compton upscattering of prompt and afterglow photons by shock-heated thermal plasma. At its peak the high-energy radiation carries a significant fraction of the power dissipated at the forward shock. We discuss in detail the expected TeV luminosity, using a robust “minimal” emission model. Then, using the statistical properties of the GRB population (luminosity function, redshift distribution, afterglow energy), we simulate the expected detection rates of GRBs by current and upcoming atmospheric Cherenkov instruments. We find that GRBs exploding into a low-density interstellar medium must produce TeV emission that would have already been detected by the currently operating Cherenkov telescopes. The absence of detections is consistent with explosions into a dense wind of the GRB progenitor. If, as suggested by the recent analysis of Fermi LAT data, the typical environment of long GRBs is a Wolf-Rayet progenitor wind with the density parameter A˜ {10}11 g cm-1, then 10%-20% of the bursts that trigger the space-borne detectors should also be detectable by the upcoming Cherenkov Telescope Array (CTA) under favorable observing conditions. Since absorption by the extragalactic background light limits the detectability above 0.1 TeV for all but the most nearby bursts (z≲ 1), the reduced energy threshold of CTA is the key improvement over current instruments, which should increase the number of detectable bursts by at least a factor of 3 compared with currently operating facilities.

  14. Blockwise Repeated Burst Error Correcting Linear Codes

    Directory of Open Access Journals (Sweden)

    B.K. Dass

    2010-12-01

    Full Text Available This paper presents a lower and an upper bound on the number of parity check digits required for a linear code that corrects a single sub-block containing errors which are in the form of 2-repeated bursts of length b or less. An illustration of such kind of codes has been provided. Further, the codes that correct m-repeated bursts of length b or less have also been studied.

  15. Supernovae and gamma-ray bursts connection

    Energy Technology Data Exchange (ETDEWEB)

    Valle, Massimo Della [INAF-Napoli, Capodimonte Observatory, Salita Moiariello, 16, I-80131 Napoli (Italy); International Center for Relativistic Astrophysics Network, Piazzale della Repubblica 10, I-65122, Pescara (Italy)

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  16. High-energy emission from bright gamma-ray bursts using Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Bissaldi, Elisabetta

    2010-05-25

    Among the scientific objectives of one of the present NASA missions, the Fermi Gamma-ray Space Telescope (FGST), is the study of gamma-ray bursts (GRBs). Fermi's payload comprises two science instruments, the Large Area Telescope (LAT) and the Gamma-Ray Burst Monitor (GBM). GBM was designed to detect and localize bursts for the Fermi mission. By means of an array of 12 NaI(Tl) (8 keV to 1 MeV) and two BGO (0.2 to 40 MeV) scintillation detectors, GBM extends the energy range (20 MeV to > 300 GeV) of the LAT instrument into the traditional range of current GRB databases. The physical detector response of the GBM instrument to GRBs has been determined with the help of Monte Carlo simulations, which are supported and verified by on-ground individual detector calibration measurements. The GBM detectors have been calibrated from 10 keV to 17.5 MeV using various gamma sources, and the detector response has been derived by simulations over the entire energy range (8 keV to 40 MeV) using GEANT. The GBM instrument has been operating successfully in orbit since June 11, 2008. The total trigger count from the time GBM triggering was enabled in July 2008 through December 2009 is 655, and about 380 of these triggers were classified as GRBs. Moreover, GBM detected several bursts in common with the LAT. These amazing detections mainly fulfill the primary science goal of GBM, which is the joint analysis of spectra and time histories of GRBs observed by both Fermi instruments. For every trigger, GBM provides near-real time on-board burst locations to permit repointing of the spacecraft and to obtain LAT observations of delayed emission from bursts. GBM and LAT refined locations are rapidly disseminated to the scientific community, often permitting extensive multiwavelength follow-up observations by NASA's Swift mission or other space- based observatories, and by numerous ground-based telescopes, thus allowing redshift determinations. Calculations of LAT upper limits are

  17. Modeling Pilot State in Next Generation Aircraft Alert Systems

    Science.gov (United States)

    Carlin, Alan S.; Alexander, Amy L.; Schurr, Nathan

    2011-01-01

    The Next Generation Air Transportation System will introduce new, advanced sensor technologies into the cockpit that must convey a large number of potentially complex alerts. Our work focuses on the challenges associated with prioritizing aircraft sensor alerts in a quick and efficient manner, essentially determining when and how to alert the pilot This "alert decision" becomes very difficult in NextGen due to the following challenges: 1) the increasing number of potential hazards, 2) the uncertainty associated with the state of potential hazards as well as pilot slate , and 3) the limited time to make safely-critical decisions. In this paper, we focus on pilot state and present a model for anticipating duration and quality of pilot behavior, for use in a larger system which issues aircraft alerts. We estimate pilot workload, which we model as being dependent on factors including mental effort, task demands. and task performance. We perform a mathematically rigorous analysis of the model and resulting alerting plans. We simulate the model in software and present simulated results with respect to manipulation of the pilot measures.

  18. Modafinil enhances alerting-related brain activity in attention networks.

    Science.gov (United States)

    Ikeda, Yumiko; Funayama, Takuya; Tateno, Amane; Fukayama, Haruhisa; Okubo, Yoshiro; Suzuki, Hidenori

    2017-07-01

    Modafinil is a wake-promoting agent and has been reported to be effective in improving attention in patients with attentional disturbance. However, neural substrates underlying the modafinil effects on attention are not fully understood. We employed a functional magnetic resonance imaging (fMRI) study with the attention network test (ANT) task in healthy adults and examined which networks of attention are mainly affected by modafinil and which neural substrates are responsible for the drug effects. We used a randomized placebo-controlled within-subjects cross-over design. Twenty-three healthy adults participated in two series of an fMRI study, taking either a placebo or modafinil. The participants performed the ANT task, which is designed to measure three distinct attentional networks, alerting, orienting, and executive control, during the fMRI scanning. The effects of modafinil on behavioral performance and regional brain activity were analyzed. We found that modafinil enhanced alerting performance and showed greater alerting network activity in the left middle and inferior occipital gyri as compared with the placebo. The brain activations in the occipital regions were positively correlated with alerting performance. Modafinil enhanced alerting performance and increased activation in the occipital lobe in the alerting network possibly relevant to noradrenergic activity during the ANT task. The present study may provide a rationale for the treatment of patients with distinct symptoms of impaired attention.

  19. Phase analysis method for burst onset prediction

    Science.gov (United States)

    Stellino, Flavio; Mazzoni, Alberto; Storace, Marco

    2017-02-01

    The response of bursting neurons to fluctuating inputs is usually hard to predict, due to their strong nonlinearity. For the same reason, decoding the injected stimulus from the activity of a bursting neuron is generally difficult. In this paper we propose a method describing (for neuron models) a mechanism of phase coding relating the burst onsets with the phase profile of the input current. This relation suggests that burst onset may provide a way for postsynaptic neurons to track the input phase. Moreover, we define a method of phase decoding to solve the inverse problem and estimate the likelihood of burst onset given the input state. Both methods are presented here in a unified framework, describing a complete coding-decoding procedure. This procedure is tested by using different neuron models, stimulated with different inputs (stochastic, sinusoidal, up, and down states). The results obtained show the efficacy and broad range of application of the proposed methods. Possible applications range from the study of sensory information processing, in which phase-of-firing codes are known to play a crucial role, to clinical applications such as deep brain stimulation, helping to design stimuli in order to trigger or prevent neural bursting.

  20. On Gamma-Ray Bursts

    Science.gov (United States)

    Ruffini, R.; Bernardini, M. G.; Bianco, C. L.; Caito, L.; Chardonnet, P.; Cherubini, C.; Dainotti, M. G.; Fraschetti, F.; Geralico, A.; Guida, R.; Patricelli, B.; Rotondo, M.; Rueda Hernandez, J. A.; Vereshchagin, G.; Xue, S.-S.

    2008-09-01

    We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the process of gravitational collapse, leading to the creation of an electron-positron-photon plasma: the basic self-accelerating system explaining both the energetics and the high energy Lorentz factor observed in GRBs. We then turn to recall the two basic interpretational paradigms of our GRB model: 1) the Relative Space-Time Transformation (RSTT) paradigm and 2) the Interpretation of the Burst Structure (IBS) paradigm. These paradigms lead to a "canonical" GRB light curve formed from two different components: a Proper-GRB (P-GRB) and an extended afterglow comprising a raising part, a peak, and a decaying tail. When the P-GRB is energetically predominant we have a "genuine" short GRB, while when the afterglow is energetically predominant we have a so-called long GRB or a "fake" short GRB. We compare and contrast the description of the relativistic expansion of the electron-positron plasma within our approach and within the other ones in the current literature. We then turn

  1. Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

    Science.gov (United States)

    Lee, B.; Akerlof, C.; Ables, E.; Bionta, R. M.; Ott, L.; Park, H. S.; Parker, E.; Barthelmy, S.; Butterworth, P.; Cline, T.

    1995-01-01

    The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.

  2. EDGE: Explorer of diffuse emission and gamma-ray burst explosions

    DEFF Research Database (Denmark)

    Den Herder, J.W.; Hermsen, W.; Hoevers, H.

    2007-01-01

    How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysics. EDGE1 will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions, through the period of galaxy......). This enables the study of their (star-forming) environment and the use of GRBs as back lights of large scale cosmological structures; (b) observing and surveying extended sources (galaxy clusters, WHIM) with high sensitivity using two wide field of view X-ray telescopes (one with a high angular resolution...

  3. Time Resolved Spectroscopy of SGR J1550-5418 Bursts Detected with Fermi/Gamma-Ray Burst Monitor

    NARCIS (Netherlands)

    Younes, G.; Kouveliotou, C.; van der Horst, A.J.; Baring, M.G.; Granot, J.; Watts, A.L.; Bhat, P.N.; Collazzi, A.; Gehrels, N.; Gorgone, N.; Göğüş, E.; Gruber, D.; Grunblatt, S.; Huppenkothen, D.; Kaneko, Y.; von Kienlin, A.; van der Klis, M.; Lin, L.; Mcenery, J.; van Putten, T.; Wijers, R.A.M.J.

    2014-01-01

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550-5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a

  4. Space Telescope Systems Description Handbook

    Science.gov (United States)

    Carter, R. E.

    1985-01-01

    The objective of the Space Telescope Project is to orbit a high quality optical 2.4-meter telescope system by the Space Shuttle for use by the astronomical community in conjunction with NASA. The scientific objectives of the Space Telescope are to determine the constitution, physical characteristics, and dynamics of celestial bodies; the nature of processes which occur in the extreme physical conditions existing in stellar objects; the history and evolution of the universe; and whether the laws of nature are universal in the space-time continuum. Like ground-based telescopes, the Space Telescope was designed as a general-purpose instrument, capable of utilizing a wide variety of scientific instruments at its focal plane. This multi-purpose characteristic will allow the Space Telescope to be effectively used as a national facility, capable of supporting the astronomical needs for an international user community and hence making contributions to man's needs. By using the Space Shuttle to provide scientific instrument upgrading and subsystems maintenance, the useful and effective operational lifetime of the Space Telescope will be extended to a decade or more.

  5. The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, W.B.; /UC, Santa Cruz; Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Anderson, B. /UC, Santa Cruz; Axelsson, M.; /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bartelt, J.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bederede, D.; /DAPNIA, Saclay; Bellardi, F.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bignami, G.F.; /Pavia U.; Bisello, D.; /INFN, Padua /Padua U.; Bissaldi, E.; /Garching, Max Planck Inst., MPE; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /INFN, Padua /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASI, Rome /INFN, Pisa /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..

    2009-05-15

    The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3

  6. VLBA Locates Origin of Superenergetic Bursts Near Giant Black Hole

    Science.gov (United States)

    2009-07-01

    Using a worldwide combination of diverse telescopes, astronomers have discovered that a giant galaxy's bursts of very high energy gamma rays are coming from a region very close to the supermassive black hole at its core. The discovery provides important new information about the mysterious workings of the powerful "engines" in the centers of innumerable galaxies throughout the Universe. M87 Zooming in on the powerful core of the galaxy M87 CREDIT: Bill Saxton, NRAO/AUI/NSF Full Page of Graphics The galaxy M87, 50 million light-years from Earth, harbors at its center a black hole more than six billion times more massive than the Sun. Black holes are concentrations of matter so dense that not even light can escape their gravitational pull. The black hole is believed to draw material from its surroundings -- material that, as it falls toward the black hole, forms a tightly-rotating disk. Processes near this accretion disk, powered by the immense gravitational energy of the black hole, propel energetic material outward for thousands of light-years. This produces the "jets" seen emerging from many galaxies. In 1998, astronomers found that M87 also was emitting flares of gamma rays a trillion times more energetic than visible light. However, the telescopes that discovered these bursts of very high energy gamma rays could not determine exactly where in the galaxy they originated. In 2007 and 2008, the astronomers using these gamma-ray telescopes combined forces with a team using the National Science Foundation's continent-wide Very Long Baseline Array (VLBA), a radio telescope with extremely high resolving power, or ability to see fine detail. "Combining the gamma-ray observations with the supersharp radio 'vision' of the VLBA allowed us to see that the gamma rays are coming from a region very near the black hole itself," said Craig Walker, of the National Radio Astronomy Observatory (NRAO). "Pinning down this location addresses what was an open question and provides

  7. Speech Auditory Alerts Promote Memory for Alerted Events in a Video-Simulated Self-Driving Car Ride.

    Science.gov (United States)

    Nees, Michael A; Helbein, Benji; Porter, Anna

    2016-05-01

    Auditory displays could be essential to helping drivers maintain situation awareness in autonomous vehicles, but to date, few or no studies have examined the effectiveness of different types of auditory displays for this application scenario. Recent advances in the development of autonomous vehicles (i.e., self-driving cars) have suggested that widespread automation of driving may be tenable in the near future. Drivers may be required to monitor the status of automation programs and vehicle conditions as they engage in secondary leisure or work tasks (entertainment, communication, etc.) in autonomous vehicles. An experiment compared memory for alerted events-a component of Level 1 situation awareness-using speech alerts, auditory icons, and a visual control condition during a video-simulated self-driving car ride with a visual secondary task. The alerts gave information about the vehicle's operating status and the driving scenario. Speech alerts resulted in better memory for alerted events. Both auditory display types resulted in less perceived effort devoted toward the study tasks but also greater perceived annoyance with the alerts. Speech auditory displays promoted Level 1 situation awareness during a simulation of a ride in a self-driving vehicle under routine conditions, but annoyance remains a concern with auditory displays. Speech auditory displays showed promise as a means of increasing Level 1 situation awareness of routine scenarios during an autonomous vehicle ride with an unrelated secondary task. © 2016, Human Factors and Ergonomics Society.

  8. Optimizing the design of the EXIST mission and its potential for gamma ray burst discoveries

    Science.gov (United States)

    Garson, Alfred Bates, III

    This thesis concerns design studies for EXIST (Energetic X-ray Imaging Survey Telescope), a future hard X-ray, wide field-of-view, survey telescope. Scanning the full sky every 95 minutes, EXIST will search for black holes and gamma-ray bursts (GRBs). The work involves the background in EXIST's CZT detectors due to radiation environments of possible orbits. In the study, both prompt and delayed background rates are considered. Shielding options are evaluated for their ability to reduce the background rates in EXIST's high-energy detectors. In addition, I examine the feasibility of using active shielding to detect and measure the energy spectra of GRBs. I also incorporate different star formation histories produced from semi-analytical models to evaluate EXIST's potential for detecting GRBs originating as early as 200 million years after the big bang.

  9. Method and apparatus for coherent burst ranging

    Science.gov (United States)

    Wachter, Eric A.; Fisher, Walter G.

    1998-01-01

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.

  10. Gamma Ray burst detection and localization capabilities of the IBIS/INTEGRAL telescope Compton mode

    Energy Technology Data Exchange (ETDEWEB)

    Marcinkowski, R.; Denis, M. [CBK, Warsaw (Poland); Laurent, Ph.; Goldoni, P. [SAp CEA, Gif sur Yvette (France); APC, UMR, Paris (France); Bulik, T. [CAMK, Warsaw (Poland); Rau, A. [MPE, Garching (Germany)

    2005-07-15

    We present the capabilities of the IBIS/INTEGRAL Compton mode for the detection and localization of GRBs. Based on the example of GRB 030406 we demonstrate that the IBIS Compton mode is able to detect a GRB and (if it is strong enough) localize it with an accuracy of a few degrees. Energetic spectra extraction is also possible in the range from a few hundred keV to a few MeV.

  11. QKD-Based Secured Burst Integrity Design for Optical Burst Switched Networks

    Science.gov (United States)

    Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

    2016-03-01

    The field of optical transmission has undergone numerous advancements and is still being researched mainly due to the fact that optical data transmission can be done at enormous speeds. It is quite evident that people prefer optical communication when it comes to large amount of data involving its transmission. The concept of switching in networks has matured enormously with several researches, architecture to implement and methods starting with Optical circuit switching to Optical Burst Switching. Optical burst switching is regarded as viable solution for switching bursts over networks but has several security vulnerabilities. However, this work exploited the security issues associated with Optical Burst Switching with respect to integrity of burst. This proposed Quantum Key based Secure Hash Algorithm (QKBSHA-512) with enhanced compression function design provides better avalanche effect over the conventional integrity algorithms.

  12. The James Webb Space Telescope

    Science.gov (United States)

    Mather, John C.

    2004-01-01

    The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope (HST) and the Spitzer Space Telescope (SST) by deploying a large cooled infrared telescope around the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 microns, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives and the ability of the system to meet them. I will close with a summary of possible future IR space missions, ranging from the far IR to planet-finding coronagraphs and interferometers

  13. Large aperture Fresnel telescopes/011

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R.A., LLNL

    1998-07-16

    At Livermore we`ve spent the last two years examining an alternative approach towards very large aperture (VLA) telescopes, one based upon transmissive Fresnel lenses rather than on mirrors. Fresnel lenses are attractive for VLA telescopes because they are launchable (lightweight, packagable, and deployable) and because they virtually eliminate the traditional, very tight, surface shape requirements faced by reflecting telescopes. Their (potentially severe) optical drawback, a very narrow spectral bandwidth, can be eliminated by use of a second (much smaller) chromatically-correcting Fresnel element. This enables Fresnel VLA telescopes to provide either single band ({Delta}{lambda}/{lambda} {approximately} 0.1), multiple band, or continuous spectral coverage. Building and fielding such large Fresnel lenses will present a significant challenge, but one which appears, with effort, to be solvable.

  14. The Design and Capabilities of the EXIST Optical and Infra-Red Telescope (IRT)

    Science.gov (United States)

    Kutyrev, A S.; Moseley, S. H.; Golisano, C.; Gong, Q.; Allen, B. T.; Gehrels, N.; Grindlay, J. E.; Hong, J. S.; Woodgate, B. E.

    2010-01-01

    The Infra-Red Telescope is a critical element of the EXIST (Energetic X-Ray Imaging Survey Telescope) observatory. The primary goal of the IRT is to obtain photometric and spectroscopic measurements of high redshift (> or =6) gamma ray reaching to the epoque of reionization. The photometric and spectral capabilities of the IRT will allow to use GRB afterglow as probes of the composition and ionization state of the intergalactic medium of the young universe. A prompt follow up (within three minutes) of the transient discovered by the EXIST makes IRT a unique tool for detection and study of these events in the infrared and optical wavelength, which is particularly valuable at wavelengths unavailable to the ground based observatories. We present the results of the mission study development on the IRT as part of the EXIST observatory. Keywords: infrared spectroscopy, space telescope, gamma ray bursts, early universe

  15. Drug interaction alert override rates in the Meaningful Use era: no evidence of progress.

    Science.gov (United States)

    Bryant, A D; Fletcher, G S; Payne, T H

    2014-01-01

    Interruptive drug interaction alerts may reduce adverse drug events and are required for Stage I Meaningful Use attestation. For the last decade override rates have been very high. Despite their widespread use in commercial EHR systems, previously described interventions to improve alert frequency and acceptance have not been well studied. (1) To measure override rates of inpatient medication alerts within a commercial clinical decision support system, and assess the impact of local customization efforts. (2) To compare override rates between drug-drug interaction and drug-allergy interaction alerts, between attending and resident physicians, and between public and academic hospitals. (3) To measure the correlation between physicians' individual alert quantities and override rates as an indicator of potential alert fatigue. We retrospectively analyzed physician responses to drug-drug and drug-allergy interaction alerts, as generated by a common decision support product in a large teaching hospital system. (1) Over four days, 461 different physicians entered 18,354 medication orders, resulting in 2,455 visible alerts; 2,280 alerts (93%) were overridden. (2) The drug-drug alert override rate was 95.1%, statistically higher than the rate for drug-allergy alerts (90.9%) (p drug interaction alert system and to reduce alerting, override rates remain as high as reported over a decade ago. Alert fatigue does not seem to contribute. The results suggest the need to fundamentally question the premises of drug interaction alert systems.

  16. Comparison of methods of alert acknowledgement by critical care clinicians in the ICU setting

    Directory of Open Access Journals (Sweden)

    Andrew M. Harrison

    2017-03-01

    Full Text Available Background Electronic Health Record (EHR-based sepsis alert systems have failed to demonstrate improvements in clinically meaningful endpoints. However, the effect of implementation barriers on the success of new sepsis alert systems is rarely explored. Objective To test the hypothesis time to severe sepsis alert acknowledgement by critical care clinicians in the ICU setting would be reduced using an EHR-based alert acknowledgement system compared to a text paging-based system. Study Design In one arm of this simulation study, real alerts for patients in the medical ICU were delivered to critical care clinicians through the EHR. In the other arm, simulated alerts were delivered through text paging. The primary outcome was time to alert acknowledgement. The secondary outcomes were a structured, mixed quantitative/qualitative survey and informal group interview. Results The alert acknowledgement rate from the severe sepsis alert system was 3% (N = 148 and 51% (N = 156 from simulated severe sepsis alerts through traditional text paging. Time to alert acknowledgement from the severe sepsis alert system was median 274 min (N = 5 and median 2 min (N = 80 from text paging. The response rate from the EHR-based alert system was insufficient to compare primary measures. However, secondary measures revealed important barriers. Conclusion Alert fatigue, interruption, human error, and information overload are barriers to alert and simulation studies in the ICU setting.

  17. Non-Equilibrium Thermodynamics of Transcriptional Bursts

    Science.gov (United States)

    Hernández-Lemus, Enrique

    Gene transcription or Gene Expression (GE) is the process which transforms the information encoded in DNA into a functional RNA message. It is known that GE can occur in bursts or pulses. Transcription is irregular, with strong periods of activity, interspersed by long periods of inactivity. If we consider the average behavior over millions of cells, this process appears to be continuous. But at the individual cell level, there is considerable variability, and for most genes, very little activity at any one time. Some have claimed that GE bursting can account for the high variability in gene expression occurring between cells in isogenic populations. This variability has a big impact on cell behavior and thus on phenotypic conditions and disease. In view of these facts, the development of a thermodynamic framework to study gene expression and transcriptional regulation to integrate the vast amount of molecular biophysical GE data is appealing. Application of such thermodynamic formalism is useful to observe various dissipative phenomena in GE regulatory dynamics. In this chapter we will examine at some detail the complex phenomena of transcriptional bursts (specially of a certain class of anomalous bursts) in the context of a non-equilibrium thermodynamics formalism and will make some initial comments on the relevance of some irreversible processes that may be connected to anomalous transcriptional bursts.

  18. Scientific Applications Performance Evaluation on Burst Buffer

    KAUST Repository

    Markomanolis, George S.

    2017-10-19

    Parallel I/O is an integral component of modern high performance computing, especially in storing and processing very large datasets, such as the case of seismic imaging, CFD, combustion and weather modeling. The storage hierarchy includes nowadays additional layers, the latest being the usage of SSD-based storage as a Burst Buffer for I/O acceleration. We present an in-depth analysis on how to use Burst Buffer for specific cases and how the internal MPI I/O aggregators operate according to the options that the user provides during his job submission. We analyze the performance of a range of I/O intensive scientific applications, at various scales on a large installation of Lustre parallel file system compared to an SSD-based Burst Buffer. Our results show a performance improvement over Lustre when using Burst Buffer. Moreover, we show results from a data hierarchy library which indicate that the standard I/O approaches are not enough to get the expected performance from this technology. The performance gain on the total execution time of the studied applications is between 1.16 and 3 times compared to Lustre. One of the test cases achieved an impressive I/O throughput of 900 GB/s on Burst Buffer.

  19. The origins of the telescope

    OpenAIRE

    van Helden, A.; Dupré, S.; van Gent, R.; Zuidervaart, H.J.

    2011-01-01

    The origins of the telescope have been debated since the instrument’s appearance in the Hague in 1608. Civic and national pride has led local dignitaries, popular writers, and scholars to present sharply divergent histories over the years, crediting a variety of people and places with the invention. Drawing on newly discovered documents, re-examined records, and tests of early lenses and telescopes, this fascinating study proposes a new and convincing account of the origins of the instrument ...

  20. Hubble Space Telescope-Illustration

    Science.gov (United States)

    1989-01-01

    This illustration depicts a side view of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  1. The Large Binocular Telescope Project

    Science.gov (United States)

    Hill, J. M.

    1994-12-01

    The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astronomico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in late fall 1995 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia. Construction

  2. Duplicated laboratory tests: evaluation of a computerized alert intervention abstract.

    Science.gov (United States)

    Bridges, Sharon A; Papa, Linda; Norris, Anne E; Chase, Susan K

    2014-01-01

    Redundant testing contributes to reductions in healthcare system efficiency. The purpose of this study was to: (1) determine if the use of a computerized alert would reduce the number and cost of duplicated Acute Hepatitis Profile (AHP) laboratory tests and (2) assess what patient, test, and system factors were associated with duplication. This study used a quasi-experimental pre- and post-test design to determine the proportion of duplication of the AHP test before and after implementation of a computerized alert intervention. The AHP test was duplicated if the test was requested again within 15 days of the initial test being performed and the result present in the medical record. The intervention consisted of a computerized alert (pop-up window) that indicated to the clinician that the test had recently been ordered. A total of 674 AHP tests were performed in the pre-intervention period and 692 in the postintervention group. In the pre-intervention period, 53 (7.9%) were duplicated and in postintervention, 18 (2.6%) were duplicated (pimplementation of the alert was shown to significantly reduce associated costs of duplicated AHP tests (p≤.001). Implementation of computerized alerts may be useful in reducing duplicate laboratory tests and improving healthcare system efficiency. © 2012 National Association for Healthcare Quality.

  3. Demonstration Telescopes Using "Dollar Optics"

    Science.gov (United States)

    Ross, Paul

    2008-05-01

    I propose a poster that illustrates the use of "dollar optics” for experimentation and for the creation of demonstration telescopes. Handling a variety of lenses and mirrors provides an opportunity for discovering practical optics. Some part of this path of exploration must have been traveled by Galileo as he experimented with spectacle lenses. "Dollar optics” include reading glasses (positive meniscus lenses), convex and concave mirrors, Fresnel sheets, magnifying lenses, and eye loupes. Unwanted distance spectacles (negative meniscus lenses) are available at second-hand stores. Galileo telescopes, "long” 17th century telescopes, and useful demonstration models of Newtonian reflectors can be made with "dollar” optics. The poster will illustrate practical information about "dollar optics” and telescopes: magnification, focal length, and "diopters” disassembling spectacles; creating cheap mounts for spectacle lenses; the importance of optical axes and alignment; eyepieces; and focusing. (A table would be useful with the poster to set out a hands-on display of "dollar optic” telescopes.) Educators, experimenters, and those concerned with astronomy outreach might be interested in this poster. Working with "dollar optics” requires facility with simple tools, interest in planning projects, patience, imagination, and the willingness to invest some time and effort. "Dollar optics” may help to foster creativity and hands-on enthusiasm - as did Galileo's work with simple lenses 400 years ago. "Oh! When will there be an end put to the new observations and discoveries of this admirable instrument?” - Galileo Galilei as quoted by Henry C. King, The History of the Telescope.

  4. Bursting activity spreading through asymmetric interactions

    CERN Document Server

    Onaga, Tomokatsu

    2014-01-01

    People communicate with those who have the same background or share a common interest by using a social networking service (SNS). News or messages propagate through inhomogeneous connections in an SNS by sharing or facilitating additional comments. Such human activity is known to lead to endogenous bursting in the rate of message occurrences. We analyze a multi-dimensional self-exciting process to reveal dependence of the bursting activity on the topology of connections and the distribution of interaction strength on the connections. We determine the critical conditions for the cases where interaction strength is regulated at either the point of input or output for each person. In the input regulation condition, the network may exhibit bursting with infinitesimal interaction strength, if the dispersion of the degrees diverges as in the scale-free networks. In contrast, in the output regulation condition, the critical value of interaction strength, represented by the average number of events added by a single ...

  5. Burst Searches for Compact Binary Coalescences

    Science.gov (United States)

    Klimenko, Sergey

    2014-03-01

    Compact Binary coalescences (CBC) are the most promising sources of gravitational waves (GW) for the first detection with advanced GW detectors. Being the most efficient GW emitters among anticipated GW sources, they are also well understood theoretically in the framework of General Relativity. In the talk I'll discuss different flavors of CBC sources and two types of search methods employed in the GW data analysis: template and excess power. While template methods are the most optimal for CBC sources, I will concentrate on the excess power methods, which are typical for searches of generic GW transients (bursts). How to use burst searches for CBC sources? Why would we do this? What can we learn about CBC sources from a burst search? - these and other questions will be discussed in the talk. Supported by NSF grant PHY-1205512.

  6. CONSERVATIVE TREATMENT FOR THORACOLUMBAR SPINE BURST FRACTURES

    Directory of Open Access Journals (Sweden)

    Barajas Vanegas Raymundo

    Full Text Available ABSTRACT Objective: To identify the category of evidence and the strength of recommendation for the conservative treatment of thoracolumbar spine burst fractures. Method: A systematic review was conducted from April 2014 to June 2015, selecting articles according to their prospective design, related to thoracolumbar spine burst fractures and their treatment. These studies were published in the electronic bibliographic databases from January 2009 to January 2015. Results: A total of 9,504 articles were found in a free search, of which 7 met the selection criteria and were included for analysis in a study of a total of 435 patients, of whom 72 underwent surgical treatment and 363 received some type of conservative treatment, showing predominantly level of evidence "1b", with strength of recommendation type "A". Conclusions: According to the evidence obtained, the conservative treatment is a choice for patients with stable burst fracture in a single level of thoracolumbar spine and with no neurological injury.

  7. Gamma Ray Bursts Observations and Theoretical Conjectures

    CERN Document Server

    Alagoz, E; Carrillo, C; Golup, G T; Grimes, M; Herrera, Mora C; Gallo, Palomino J L; López, Vega A; Wicht, J

    2008-01-01

    Gamma Ray Bursts (GRBs) are short bursts of very high energy photons which were discovered in the late 1960s. Ever since their discovery, scientists have wondered about their origin. Nowadays it is known that they originate outside the Milky Way because of their high red shift rst measured in the afterglows thanks to the Beppo-SAX satellite and ground-based observations. However, theoreticians still do not agree about the mechanism that generates the bursts, and different competing models are animatedly debated. Current GRB experiments include the Swift satellite and the Pierre Auger Observatory that could detect GRBs with an increase of the background. A forthcoming dedicated experiment is GLAST, a satellite observatory for detecting gamma rays with energies up to 300 GeV, whose launch is scheduled for early 2008.

  8. Mechanism behind Erosive Bursts In Porous Media

    Science.gov (United States)

    Jäger, R.; Mendoza, M.; Herrmann, H. J.

    2017-09-01

    Erosion and deposition during flow through porous media can lead to large erosive bursts that manifest as jumps in permeability and pressure loss. Here we reveal that the cause of these bursts is the reopening of clogged pores when the pressure difference between two opposite sites of the pore surpasses a certain threshold. We perform numerical simulations of flow through porous media and compare our predictions to experimental results, recovering with excellent agreement shape and power-law distribution of pressure loss jumps, and the behavior of the permeability jumps as a function of particle concentration. Furthermore, we find that erosive bursts only occur for pressure gradient thresholds within the range of two critical values, independent of how the flow is driven. Our findings provide a better understanding of sudden sand production in oil wells and breakthrough in filtration.

  9. X-ray bursts observed with JEM-X

    DEFF Research Database (Denmark)

    Brandt, Søren Kristian; Chenevez, Jérôme; Lund, Niels

    2006-01-01

    We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found.......We report on the search for X-ray bursts in the JEM-X X-ray monitor on INTEGRAL during the first two years of operations. More than 350 bursts from 25 different type-I X-ray burst sources were found....

  10. Broadband Spectral Investigations of Magnetar Bursts

    Science.gov (United States)

    Kırmızıbayrak, Demet; Şaşmaz Muş, Sinem; Kaneko, Yuki; Göğüş, Ersin

    2017-09-01

    We present our broadband (2-250 keV) time-averaged spectral analysis of 388 bursts from SGR J1550-5418, SGR 1900+14, and SGR 1806-20 detected with the Rossi X-ray Timing Explorer (RXTE) here and as a database in a companion web-catalog. We find that two blackbody functions (BB+BB), the sum of two modified blackbody functions (LB+LB), the sum of a blackbody function and a power-law function (BB+PO), and a power law with a high-energy exponential cutoff (COMPT) all provide acceptable fits at similar levels. We performed numerical simulations to constrain the best fitting model for each burst spectrum and found that 67.6% of burst spectra with well-constrained parameters are better described by the Comptonized model. We also found that 64.7% of these burst spectra are better described with the LB+LB model, which is employed in the spectral analysis of a soft gamma repeater (SGR) for the first time here, than with the BB+BB and BB+PO models. We found a significant positive lower bound trend on photon index, suggesting a decreasing upper bound on hardness, with respect to total flux and fluence. We compare this result with bursts observed from SGR and AXP (anomalous X-ray pulsar) sources and suggest that the relationship is a distinctive characteristic between the two. We confirm a significant anticorrelation between burst emission area and blackbody temperature, and find that it varies between the hot and cool blackbody temperatures differently than previously discussed. We expand on the interpretation of our results in the framework of a strongly magnetized neutron star.

  11. Broadband Spectral Investigations of Magnetar Bursts

    Energy Technology Data Exchange (ETDEWEB)

    Kırmızıbayrak, Demet; Şaşmaz Muş, Sinem; Kaneko, Yuki; Göğüş, Ersin, E-mail: demetk@sabanciuniv.edu [Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı Tuzla, Istanbul 34956 (Turkey)

    2017-09-01

    We present our broadband (2–250 keV) time-averaged spectral analysis of 388 bursts from SGR J1550−5418, SGR 1900+14, and SGR 1806−20 detected with the Rossi X-ray Timing Explorer ( RXTE ) here and as a database in a companion web-catalog. We find that two blackbody functions (BB+BB), the sum of two modified blackbody functions (LB+LB), the sum of a blackbody function and a power-law function (BB+PO), and a power law with a high-energy exponential cutoff (COMPT) all provide acceptable fits at similar levels. We performed numerical simulations to constrain the best fitting model for each burst spectrum and found that 67.6% of burst spectra with well-constrained parameters are better described by the Comptonized model. We also found that 64.7% of these burst spectra are better described with the LB+LB model, which is employed in the spectral analysis of a soft gamma repeater (SGR) for the first time here, than with the BB+BB and BB+PO models. We found a significant positive lower bound trend on photon index, suggesting a decreasing upper bound on hardness, with respect to total flux and fluence. We compare this result with bursts observed from SGR and AXP (anomalous X-ray pulsar) sources and suggest that the relationship is a distinctive characteristic between the two. We confirm a significant anticorrelation between burst emission area and blackbody temperature, and find that it varies between the hot and cool blackbody temperatures differently than previously discussed. We expand on the interpretation of our results in the framework of a strongly magnetized neutron star.

  12. Dopamine in motivational control: rewarding, aversive, and alerting

    Science.gov (United States)

    Bromberg-Martin, Ethan S.; Matsumoto, Masayuki; Hikosaka, Okihide

    2010-01-01

    SUMMARY Midbrain dopamine neurons are well known for their strong responses to rewards and their critical role in positive motivation. It has become increasingly clear, however, that dopamine neurons also transmit signals related to salient but non-rewarding experiences such as aversive and alerting events. Here we review recent advances in understanding the reward and non-reward functions of dopamine. Based on this data, we propose that dopamine neurons come in multiple types that are connected with distinct brain networks and have distinct roles in motivational control. Some dopamine neurons encode motivational value, supporting brain networks for seeking, evaluation, and value learning. Others encode motivational salience, supporting brain networks for orienting, cognition, and general motivation. Both types of dopamine neurons are augmented by an alerting signal involved in rapid detection of potentially important sensory cues. We hypothesize that these dopaminergic pathways for value, salience, and alerting cooperate to support adaptive behavior. PMID:21144997

  13. Dynamic malware containment under an epidemic model with alert

    Science.gov (United States)

    Zhang, Tianrui; Yang, Lu-Xing; Yang, Xiaofan; Wu, Yingbo; Tang, Yuan Yan

    2017-03-01

    Alerting at the early stage of malware invasion turns out to be an important complement to malware detection and elimination. This paper addresses the issue of how to dynamically contain the prevalence of malware at a lower cost, provided alerting is feasible. A controlled epidemic model with alert is established, and an optimal control problem based on the epidemic model is formulated. The optimality system for the optimal control problem is derived. The structure of an optimal control for the proposed optimal control problem is characterized under some conditions. Numerical examples show that the cost-efficiency of an optimal control strategy can be enhanced by adjusting the upper and lower bounds on admissible controls.

  14. Wireless alerting system using vibration for vehicles dashboard

    Science.gov (United States)

    Raj, Sweta; Rai, Shweta; Magaramagara, Wilbert; Sivacoumar, R.

    2017-11-01

    This paper aims at improving the engine life of any vehicle through a continuous measurement and monitoring of vital engine operational parameters and providing an effective alerting to drivers for any abnormality. Vehicles currently are using audio and visible alerting signals through alarms and light as a warning to the driver but these are not effective in noisy environments and during daylight. Through the use of the sense of feeling a driver can be alerted effectively. The need to no other vehicle parameter needs to be aided through the mobile display (phone).Thus a system is designed and implements to measure engine temperature, RPM, Oil level and Coolant level using appropriate sensors and a wireless communication (Bluetooth) is established to actuate a portable vibration control device and to read the different vehicle sensor readings through an android application for display and diagnosis.

  15. The Comparative Characteristic of Components in the Iiib-Iii Pairs According to the Observation Data Obtained by Radio Telescope URAN-2

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. N.; Konovalenko, A. A.; Dorovskiy, V. V.; Vashchishin, R. V.; Frantsuzenko, A. V.; Rucker, G.

    In this paper we analyze the properties of type IIIb and type III bursts in IIIb-III pairs observed by radio telescope URAN-2 at frequencies 16-32 MHz. We discuss pro and contra of harmonic phenomenon of decameter IIIb-III pairs.

  16. Simmer analysis of prompt burst energetics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, J.T.

    1982-03-01

    The Prompt Burst Energetics experiments are designed to measure the pressure behavior of fuel and coolant as working fluids during a hypothetical prompt burst disassembly in an LMFBR. The work presented in this report consists of a parametric study of PBE-5S, a fresh oxide fuel experiment, using SIMMER-II. The various pressure sources in the experiment are examined, and the dominant source identified as incondensable contaminant gasses in the fuel. The important modeling uncertainties and limitations of SIMMER-II as applied to these experiments are discussed.

  17. Noise-induced bursting in Rulkov model

    Science.gov (United States)

    Ryashko, L.; Slepukhina, E.; Nasyrova, V.

    2016-10-01

    A problem of mathematical modeling and analysis of the stochastic phenomena in neuronal activity is considered. As a basic example, we use the nonlinear Rulkov map-based neuron model with random disturbances. In deterministic case, this one-dimensional model demonstrates quiescence, tonic and chaotic spiking regimes. We show that due to presence of random disturbances, a new regime of noise-induced bursting is generated not only in bistability zones, but also in monostability zones. To estimate noise intensity corresponding to the onset of bursting, the stochastic sensitivity technique and confidence domains method are applied. An effciency of our approach is confirmed by the statistics of interspike intervals.

  18. Supernovae and Gamma-Ray Bursts

    Science.gov (United States)

    Livio, Mario; Panagia, Nino; Sahu, Kailash

    2001-07-01

    Participants; Preface; Gamma-ray burst-supernova relation B. Paczynski; Observations of gamma-ray bursts G. Fishman; Fireballs T. Piran; Gamma-ray mechanisms M. Rees; Prompt optical emission from gamma-ray bursts R. Kehoe, C. Akerlof, R. Balsano, S. Barthelmy, J. Bloch, P. Butterworth, D. Casperson, T. Cline, S. Fletcher, F. Frontera, G. Gisler, J. Heise, J. Hills, K. Hurley, B. Lee, S. Marshall, T. McKay, A. Pawl, L. Piro, B. Priedhorsky, J. Szymanski and J. Wren; X-ray afterglows of gamma-ray bursts L. Piro; The first year of optical-IR observations of SN1998bw I. Danziger, T. Augusteijn, J. Brewer, E. Cappellaro, V. Doublier, T. Galama, J. Gonzalez, O. Hainaut, B. Leibundgut, C. Lidman, P. Mazzali, K. Nomoto, F. Patat, J. Spyromilio, M. Turatto, J. Van Paradijs, P. Vreeswijk and J. Walsh; X-ray emission of Supernova 1998bw in the error box of GRB980425 E. Pian; Direct analysis of spectra of type Ic supernovae D. Branch; The interaction of supernovae and gamma-ray bursts with their surroundings R. Chevalier; Magnetars, soft gamma-ray repeaters and gamma-ray bursts A. Harding; Super-luminous supernova remnants Y. -H. Chu, C. -H. Chen and S. -P. Lai; The properties of hypernovae: SNe Ic 1998bw, 1997ef, and SN IIn 1997cy K. Nomoto, P. Mazzali, T. Nakamura, K. Iwanmoto, K. Maeda, T. Suzuki, M. Turatto, I. Danziger and F. Patat; Collapsars, Gamma-Ray Bursts, and Supernovae S. Woosley, A. MacFadyen and A. Heger; Pre-supernova evolution of massive stars N. Panagia and G. Bono; Radio supernovae and GRB 980425 K. Weiler, N. Panagia, R. Sramek, S. Van Dyk, M. Montes and C. Lacey; Models for Ia supernovae and evolutionary effects P. Hoflich and I. Dominguez; Deflagration to detonation A. Khokhlov; Universality in SN Iae and the Phillips relation D. Arnett; Abundances from supernovae F. -K. Thielemann, F. Brachwitz, C. Freiburghaus, S. Rosswog, K. Iwamoto, T. Nakamura, K. Nomoto, H. Umeda, K. Langanke, G. Martinez-Pinedo, D. Dean, W. Hix and M. Strayer; Sne, GRBs, and the

  19. Polyrhythmic synchronization in bursting networking motifs.

    Science.gov (United States)

    Shilnikov, Andrey; Gordon, René; Belykh, Igor

    2008-09-01

    We study the emergence of polyrhythmic dynamics of motifs which are the building block for small inhibitory-excitatory networks, such as central pattern generators controlling various locomotive behaviors of animals. We discover that the pacemaker determining the specific rhythm of such a network composed of realistic Hodgkin-Huxley-type neurons is identified through the order parameter, which is the ratio of the neurons' burst durations or of duty cycles. We analyze different configurations of the motifs and describe the universal mechanisms for synergetics of the bursting patterns. We discuss also the multistability of inhibitory networks that results in polyrhythmicity of its emergent synchronous behaviors. (c) 2008 American Institute of Physics.

  20. CISN ShakeAlert Earthquake Early Warning System Monitoring Tools

    Science.gov (United States)

    Henson, I. H.; Allen, R. M.; Neuhauser, D. S.

    2015-12-01

    CISN ShakeAlert is a prototype earthquake early warning system being developed and tested by the California Integrated Seismic Network. The system has recently been expanded to support redundant data processing and communications. It now runs on six machines at three locations with ten Apache ActiveMQ message brokers linking together 18 waveform processors, 12 event association processes and 4 Decision Module alert processes. The system ingests waveform data from about 500 stations and generates many thousands of triggers per day, from which a small portion produce earthquake alerts. We have developed interactive web browser system-monitoring tools that display near real time state-of-health and performance information. This includes station availability, trigger statistics, communication and alert latencies. Connections to regional earthquake catalogs provide a rapid assessment of the Decision Module hypocenter accuracy. Historical performance can be evaluated, including statistics for hypocenter and origin time accuracy and alert time latencies for different time periods, magnitude ranges and geographic regions. For the ElarmS event associator, individual earthquake processing histories can be examined, including details of the transmission and processing latencies associated with individual P-wave triggers. Individual station trigger and latency statistics are available. Detailed information about the ElarmS trigger association process for both alerted events and rejected events is also available. The Google Web Toolkit and Map API have been used to develop interactive web pages that link tabular and geographic information. Statistical analysis is provided by the R-Statistics System linked to a PostgreSQL database.

  1. Are fast radio bursts markers of dark core collapse?

    Science.gov (United States)

    Katz, J. I.

    2017-07-01

    Are some neutron stars produced without a supernova, without ejecting mass in a remnant? Theoretical calculations of core collapse in massive stars often predict this. The observation of the repeating FRB 121102, whose dispersion measure has not changed over several years, suggests that dark core collapses are not just failures of computer codes, but may be real. The existence of one repeating fast radio burst (FRB) with unchanging dispersion measure is not conclusive, but within a decade hundreds or thousands of FRB are expected to be discovered, likely including scores of repeaters, permitting useful statistical inferences. A naïve supernova remnant model predicts observable decline in dispersion measure for 100 yr after its formation. If an upper limit on the decline of 2 pc cm-3 yr-1 is set for five repeating FRBs, then the naïve model with nominal parameters is rejected at the 95 per cent level of confidence. This may indicate dark neutron star formation without a supernova or supernova remnant. This hypothesis may also be tested with the Large Synoptic Survey Telescope (LSST) data that would show, if present, a supernova at an interferometric FRB position if it occurred within the LSST epoch.

  2. Regularity of high energy photon events from gamma ray bursts

    Science.gov (United States)

    Xu, Haowei; Ma, Bo-Qiang

    2018-01-01

    The effect of Quantum Gravity (QG) may bring a tiny light speed variation as v(E)=c(1‑E/ELV), where E is the photon energy and ELV is a Lorentz violation scale. A remarkable regularity was suggested in previous studies to look for the light speed variation from high energy photon events of Gamma Ray Bursts (GRBs). We provide a general analysis on the data of 25 bright GRBs observed by the Fermi Gamma-ray Space Telescope (FGST). Such method allows a completed scan over all possibilities in a more clean and impartial way without any bias compared to previous intuitive analysis. The results show that with the increase in the intrinsic energies of photons, such regularity truly emerges and gradually becomes significant. For photons with intrinsic energies higher than 40 GeV, the regularity exists at a significance of 3–5 σ with ELV=3.6× 1017 GeV determined by the GRB data.

  3. A Fast Radio Burst Search Method for VLBI Observation

    Science.gov (United States)

    Liu, Lei; Tong, Fengxian; Zheng, Weimin; Zhang, Juan; Tong, Li

    2018-02-01

    We introduce the cross-spectrum-based fast radio burst (FRB) search method for Very Long Baseline Interferometer (VLBI) observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post-processing, which fully utilizes the cross-spectrum fringe phase information and therefore maximizes the power of single-pulse signals. Working with cross-spectrum greatly reduces the effect of radio frequency interference compared with using auto-power spectrum. Single-pulse detection confidence increases by cross-identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.

  4. James Webb Space Telescope Optical Telescope Element Mirror Coatings

    Science.gov (United States)

    Keski-Kuha, Ritva A.; Bowers, Charles W.; Quijada, Manuel A.; Heaney, James B.; Gallagher, Benjamin; McKay, Andrew; Stevenson, Ian

    2012-01-01

    James Webb Space Telescope (JWST) Optical Telescope Element (OTE) mirror coating program has been completed. The science goals of the JWST mission require a uniform, low stress, durable optical coating with high reflectivity over the JWST spectral region. The coating has to be environmentally stable, radiation resistant and compatible with the cryogenic operating environment. The large size, 1.52 m point to point, light weight, beryllium primary mirror (PM) segments and flawless coating process during the flight mirror coating program that consisted coating of 21 flight mirrors were among many technical challenges. This paper provides an overview of the JWST telescope mirror coating program. The paper summarizes the coating development program and performance of the flight mirrors.

  5. Geo-targeted Weather Alerts Coming to Millions of Mobile Devices

    Science.gov (United States)

    Gerber, M.

    2011-12-01

    The Personal Localized Alert Network (PLAN), aka Commercial Mobile Alert System (CMAS), is readying for roll out and will be broadcasting emergency public alerts to millions of cell phones by the middle of 2012. Learn how the National Weather Serivce (NWS) is supplying PLAN with geo-referenced weather alert information in the industry standard Common Alerting Protocol (CAP) format and how you can access this same information for integration with mobile devices, other consumer electronics, and decision support systems. Information will also be provided on the NWS' new collaborative venue that encourages wide participation in the evolution and use of NWS CAP alerts in a variety of applications.

  6. INTEGRAL monitoring of unusually long X-ray bursts

    DEFF Research Database (Denmark)

    -rich bursting regime to a pure helium regime. Moreover, a handful of long bursts have shown, before the extended decay phase, an initial spike similar to a normal short X-ray burst. Such twofold bursts might be a sort of link between short and super-bursts, where the premature ignition of a carbon layer could......Thermonuclear bursts on the surface of accreting neutron stars in low mass X-ray binaries have been studied for many years and have in a few cases confirmed theoretical models of nuclear ignition and burning mechanisms. The large majority of X-ray bursts last less than 100s. A good number...... of the known X-ray bursters are frequently observed by INTEGRAL, in particular in the frame of the Key Programmes. Taking advantage of the INTEGRAL instrumentation, an international collaboration led by the JEM-X team at the Danish National Space Institute has been monitoring the occurrence of uncommon burst...

  7. On the Nature of the Gamma-ray Bursts

    Directory of Open Access Journals (Sweden)

    Kyung-Ai Hong

    1987-12-01

    Full Text Available Review of the γ-ray burst phenomena are presented. History of the γ-ray bursts, characteristics, and three radiation mechanisms of thermal bremsstrahlung, thermal synchrotron, and inverse Compton scattering processes are considered.

  8. Robotic Astronomy and the BOOTES Network of Robotic Telescopes

    Directory of Open Access Journals (Sweden)

    A. J. Castro-Tirado

    2011-01-01

    Full Text Available The Burst Observer and Optical Transient Exploring System (BOOTES, started in 1998 as a Spanish-Czech collaboration project, devoted to a study of optical emissions from gamma ray bursts (GRBs that occur in the Universe. The first two BOOTES stations were located in Spain, and included medium size robotic telescopes with CCD cameras at the Cassegrain focus as well as all-sky cameras, with the two stations located 240 km apart. The first observing station (BOOTES-1 is located at ESAt (INTA-CEDEA in Mazag´on (Huelva and the first light was obtained in July 1998. The second observing station (BOOTES-2 is located at La Mayora (CSIC in M´alaga and has been operating fully since July 2001. In 2009 BOOTES expanded abroad, with the third station (BOOTES-3 being installed in Blenheim (South Island, New Zealand as result of a collaboration project with several institutions from the southern hemisphere. The fourth station (BOOTES-4 is on its way, to be deployed in 2011.

  9. Spectral Lag Evolution among -Ray Burst Pulses

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We analyse the spectral lag evolution of -ray burst (GRB) pulses with observations by CGRO/BATSE. No universal spectral lag evolution feature and pulse luminosity-lag relation within a GRB is observed.Our results suggest that the spectral lag would be due to radiation physics and dynamics of a given ...

  10. Radio Afterglows of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    Lekshmi Resmi

    2017-09-12

    Sep 12, 2017 ... Gamma Ray Bursts (GRBs) were serendipitously discovered in late 1960s by the Vela military satel- lites. In the following years, dedicated scanning instru- ments on-board high energy missions like BeppoSAX1,. CGRO2, HETE3, Swift4 and Fermi5 have increased the number of GRB detections to several ...

  11. Trick or Treat and Telescopes

    Science.gov (United States)

    Buratti, Bonnie J.; Meinke, Bonnie K.; Schmude, Richard W.

    2017-10-01

    Based on an activity that DPS member Richard Schmude Jr. has been doing for years, with over 5000 children reached, DPS initiated in 2016 a pilot program entitled “Trick-or-Treat and Telescopes.” DPS encouraged its members to put out their telescopes during trick-or-treat time on Halloween, in their own lawns or in a neighbor’s lawn with better viewing (or more traffic). The program will be continued in 2017. This year should offer good viewing with a waxing gibbous moon and Saturn visible. The program was also advertised though the Night Sky Network, a consortium of astronomy clubs. The following website gives advice and connections to resources.https://dps.aas.org/education/trick-or-treat-and-telescopes acknowledged.

  12. Is there cosmological time dilation in gamma-ray bursts?

    Science.gov (United States)

    Band, David L.

    1994-01-01

    Norris et al. report that the temporal structure of faint gamma-ray bursts is longer than that of bright bursts, as expected for time dilation in the cosmological models of burst origin. I show that the observed trends can easily be produced by a burst luminosity function and thus may not result from cosmological effects. A cosmological signature may be present, but the tests Norris et al. present are not powerful enough to detect these signatures.

  13. HOST GALAXIES AS GAMMA-RAY BURST DISTANCE INDICATORS

    Energy Technology Data Exchange (ETDEWEB)

    D. BAND; ET AL

    2001-01-01

    We calculate the distributions of the total burst energy, the peak luminosity and the X-ray afterglow energy using burst observations and distances to the associated host galaxies. To expand the sample, we include redshift estimates for host galaxies without spectroscopic redshifts. The methodology requires a model of the host galaxy population; we find that in the best model the burst rate is proportional to the host galaxy luminosity at the time of the burst.

  14. BurstMem: A High-Performance Burst Buffer System for Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Teng [Auburn University, Auburn, Alabama; Oral, H Sarp [ORNL; Wang, Yandong [Auburn University, Auburn, Alabama; Settlemyer, Bradley W [ORNL; Atchley, Scott [ORNL; Yu, Weikuan [Auburn University, Auburn, Alabama

    2014-01-01

    The growth of computing power on large-scale sys- tems requires commensurate high-bandwidth I/O system. Many parallel file systems are designed to provide fast sustainable I/O in response to applications soaring requirements. To meet this need, a novel system is imperative to temporarily buffer the bursty I/O and gradually flush datasets to long-term parallel file systems. In this paper, we introduce the design of BurstMem, a high- performance burst buffer system. BurstMem provides a storage framework with efficient storage and communication manage- ment strategies. Our experiments demonstrate that BurstMem is able to speed up the I/O performance of scientific applications by up to 8.5 on leadership computer systems.

  15. Early-time observations of gamma-ray burst error boxes with the Livermore optical transient imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G G

    2000-08-01

    Despite the enormous wealth of gamma-ray burst (GRB) data collected over the past several years the physical mechanism which causes these extremely powerful phenomena is still unknown. Simultaneous and early time optical observations of GRBs will likely make an great contribution t o our understanding. LOTIS is a robotic wide field-of-view telescope dedicated to the search for prompt and early-time optical afterglows from gamma-ray bursts. LOTIS began routine operations in October 1996 and since that time has responded to over 145 gamma-ray burst triggers. Although LOTIS has not yet detected prompt optical emission from a GRB its upper limits have provided constraints on the theoretical emission mechanisms. Super-LOTIS, also a robotic wide field-of-view telescope, can detect emission 100 times fainter than LOTIS is capable of detecting. Routine observations from Steward Observatory's Kitt Peak Station will begin in the immediate future. During engineering test runs under bright skies from the grounds of Lawrence Livermore National Laboratory Super-LOTIS provided its first upper limits on the early-time optical afterglow of GRBs. This dissertation provides a summary of the results from LOTIS and Super-LOTIS through the time of writing. Plans for future studies with both systems are also presented.

  16. MODELING PHOTODISINTEGRATION-INDUCED TeV PHOTON EMISSION FROM LOW-LUMINOSITY GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xuewen [Physics Department, Sichuan University, Chengdu 610065 (China); Wu Xuefeng; Lu Tan, E-mail: astrolxw@gmail.com, E-mail: xfwu@pmo.ac.cn, E-mail: t.lu@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2012-05-15

    Ultra-high-energy cosmic-ray heavy nuclei have recently been considered as originating from nearby low-luminosity gamma-ray bursts that are associated with Type Ibc supernovae. Unlike the power-law decay in long duration gamma-ray bursts, the light curve of these bursts exhibits complex UV/optical behavior: shock breakout dominated thermal radiation peaks at about 1 day, and, after that, nearly constant emission sustained by radioactive materials for tens of days. We show that the highly boosted heavy nuclei at PeV energy interacting with the UV/optical photon field will produce considerable TeV photons via the photodisintegration/photo-de-excitation process. It was later predicted that a thermal-like {gamma}-ray spectrum peaks at about a few TeV, which may serve as evidence of nucleus acceleration. The future observations by the space telescope Fermi and by the ground atmospheric Cherenkov telescopes such as H.E.S.S., VERITAS, and MAGIC will shed light on this prediction.

  17. Acute alerting effects of light : A systematic literature review

    NARCIS (Netherlands)

    Souman, Jan L.; Tinga, Angelica M.; te Pas, Susan F.|info:eu-repo/dai/nl/111010853; van Ee, Raymond|info:eu-repo/dai/nl/107286912; Vlaskamp, Björn N.S.

    2018-01-01

    Periodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of

  18. Acute alerting effects of light : a systematic literature review

    NARCIS (Netherlands)

    Souman, Jan L; Tinga, Angelica M; Te Pas, Susan F; van Ee, Raymond; Vlaskamp, Björn N S

    2017-01-01

    Periodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of

  19. Diurnal spectral sensitivity of the acute alerting effects of light.

    Science.gov (United States)

    Rahman, Shadab A; Flynn-Evans, Erin E; Aeschbach, Daniel; Brainard, George C; Czeisler, Charles A; Lockley, Steven W

    2014-02-01

    Previous studies have demonstrated short-wavelength sensitivity for the acute alerting response to nocturnal light exposure. We assessed daytime spectral sensitivity in alertness, performance, and waking electroencephalogram (EEG). Between-subjects (n = 8 per group). Inpatient intensive physiologic monitoring unit. Sixteen healthy young adults (mean age ± standard deviation = 23.8 ± 2.7 y). Equal photon density exposure (2.8 × 10(13) photons/cm(2)/s) to monochromatic 460 nm (blue) or 555 nm (green) light for 6.5 h centered in the middle of the 16-h episode of wakefulness during the biological day. Results were compared retrospectively to 16 individuals who were administered the same light exposure during the night. Daytime and nighttime 460-nm light exposure significantly improved auditory reaction time (P exposure. Whereas subjective sleepiness ratings did not differ between the two spectral conditions during the daytime (P > 0.05), 460-nm light exposure at night significantly reduced subjective sleepiness compared to 555-nm light exposure at night (P exposure improved alertness to near-daytime levels. The alerting effects of short-wavelength 460-nm light are mediated by counteracting both the circadian drive for sleepiness and homeostatic sleep pressure at night, but only via reducing the effects of homeostatic sleep pressure during the day.

  20. development of an integrated campus security alerting system

    African Journals Online (AJOL)

    user

    DEVELOPMENT OF AN INTEGRATED CAMPUS SECURITY ALERTING SYSTEM. A. Abdullahi & P. E. Orukpe. Nigerian Journal of Technology. Vol. 35, No. 4, October 2016. 896 low cost [6-7]. The wireless sensor network (WSN) consists of spatially distributed autonomous devices using sensors to cooperatively monitor ...

  1. Public Health Measures: Alerts and Early Warning Systems

    NARCIS (Netherlands)

    Marvin, H.J.P.; Kleter, G.A.

    2014-01-01

    This article reviews various reactive and proactive alert and early warning systems that can be used for the identification of emerging risks to food safety, both within the European Union and at the global level. Recent developments include the establishment of a unit dedicated to emerging risks at

  2. Monitoring epidemic alert levels by analyzing Internet search volume.

    Science.gov (United States)

    Zhou, Xichuan; Li, Qin; Zhu, Zhenglin; Zhao, Han; Tang, Hao; Feng, Yujie

    2013-02-01

    The prevention of infectious diseases is a global health priority area. The early detection of possible epidemics is the first and important defense line against infectious diseases. However, conventional surveillance systems, e.g., the Centers for Disease Control and Prevention (CDC), rely on clinical data. The CDC publishes the surveillance results weeks after epidemic outbreaks. To improve the early detection of epidemic outbreaks, we designed a syndromic surveillance system to predict the epidemic trends based on disease-related Google search volume. Specifically, we first represented the epidemic trend with multiple alert levels to reduce the noise level. Then, we predicted the epidemic alert levels using a continuous density HMM, which incorporated the intrinsic characteristic of the disease transmission for alert level estimation. Respective models are built to monitor both national and regional epidemic alert levels of the U.S. The proposed system can provide real-time surveillance results, which are weeks before the CDC's reports. This paper focusses on monitoring the infectious disease in the U.S., however, we believe similar approach may be used to monitor epidemics for the developing countries as well.

  3. Preventing drowsiness accidents by an alertness maintenance device

    NARCIS (Netherlands)

    Verwey, W.B.; Zaidel, D.M.

    1999-01-01

    The reported experiment investigated in an advanced driving simulator whether drivers' alertness can be maintained in drowsiness-inducing conditions by a special game-like system, a `gamebox'. Drowsiness was assessed by self-rating and eye-closures. Mental effort was assessed by a subjective

  4. FAB (Functionally Alert Behavior Strategies) to Improve Self-Control

    Science.gov (United States)

    Pagano, John

    2015-01-01

    This paper describes the FAB (Functionally Alert Behavior) Strategies approach to improve behavior in children and adolescents with complex behavioral challenges. FAB Strategies include evidence-based environmental adaptations, sensory modulation, positive behavioral support, and physical self-regulation strategies. FAB Strategies can be used by…

  5. Global Trade Alert | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Global Trade Alert (GTA) will provide information in real time on national measures taken during the current global economic downturn that are likely to discriminate against foreign commerce. GTA will complement and go beyond World Trade Organization (WTO) and World Bank monitoring initiatives by identifying affected ...

  6. RSS based CERN Alerter. Information broadcast to all CERN offices.

    CERN Multimedia

    Otto, R

    2007-01-01

    Nearly every large organization uses a tool to broadcast messages and information across the internal campus (messages like alerts announcing interruption in services or just information about upcoming events). These tools typically allow administrators (operators) to send "targeted" messages which are sent only to specific groups of users or computers, e/g only those located in a specified building or connected to a particular computing service. CERN has a long history of such tools: CERNVMS€™s SPM_quotMESSAGE command, Zephyr and the most recent the NICE Alerter based on the NNTP protocol. The NICE Alerter used on all Windows-based computers had to be phased out as a consequence of phasing out NNTP at CERN. The new solution to broadcast information messages on the CERN campus continues to provide the service based on cross-platform technologies, hence minimizing custom developments and relying on commercial software as much as possible. The new system, called CERN Alerter, is based on RSS (Really Simpl...

  7. R&D Alert. Volume 7, Number 3, 2005

    Science.gov (United States)

    White, Noel, Ed.

    2005-01-01

    "R&D Alert" covers issues affecting schools in the Western Regional Educational Laboratory's four-state region--Arizona, California, Nevada, and Utah--and throughout the United States. This issue focuses on early childhood education. While the importance of early childhood education has long been recognized, traditional ideas of …

  8. Alerting, Orienting, and Executive Attention in Children with ADHD

    Science.gov (United States)

    Mullane, Jennifer C.; Corkum, Penny V.; Klein, Raymond M.; McLaughlin, Elizabeth N.; Lawrence, Michael A.

    2011-01-01

    Objective: This study evaluated the alerting, orienting, and executive attention abilities of children with ADHD and their typically developing (TD) peers using a modified version of the adult attention network test (ANT-I). Method: A total of 25 children with ADHD, Combined Type (ADHD-C, mean age = 9.20 years), 20 children with ADHD,…

  9. Comparing alertness and injury severity following motor vehicular ...

    African Journals Online (AJOL)

    Background: From casual observation of injury patterns in Motor Vehicular Accidents (MVAs), it was sometimes observed that if the victim had been more alert and reacts protectively, injury severity might be reduced. Protective response is often expected to minimize the severity of injuries. Objective: To determine the ...

  10. Evaluation of health alerts from an early illness warning system in independent living.

    Science.gov (United States)

    Rantz, Marilyn J; Scott, Susan D; Miller, Steven J; Skubic, Marjorie; Phillips, Lorraine; Alexander, Greg; Koopman, Richelle J; Musterman, Katy; Back, Jessica

    2013-06-01

    Passive sensor networks were deployed in independent living apartments to monitor older adults in their home environments to detect signs of impending illness and alert clinicians so they can intervene and prevent or delay significant changes in health or functional status. A retrospective qualitative deductive content analysis was undertaken to refine health alerts to improve clinical relevance to clinicians as they use alerts in their normal workflow of routine care delivery to older adults. Clinicians completed written free-text boxes to describe actions taken (or not) as a result of each alert; they also rated the clinical significance (relevance) of each health alert on a scale of 1 to 5. Two samples of the clinician's written responses to the health alerts were analyzed after alert algorithms had been adjusted based on results of a pilot study using health alerts to enhance clinical decision-making. In the first sample, a total of 663 comments were generated by seven clinicians in response to 385 unique alerts; there are more comments than alerts because more than one clinician rated the same alert. The second sample had a total of 142 comments produced by three clinicians in response to 88 distinct alerts. The overall clinical relevance of the alerts, as judged by the content of the qualitative comments by clinicians for each alert, improved from 33.3% of the alerts in the first sample classified as clinically relevant to 43.2% in the second. The goal is to produce clinically relevant alerts that clinicians find useful in daily practice. The evaluation methods used are described to assist others as they consider building and iteratively refining health alerts to enhance clinical decision making.

  11. Development of a Standardized Rating Tool for Drug Alerts to Reduce Information Overload.

    Science.gov (United States)

    Pfistermeister, Barbara; Sedlmayr, Brita; Patapovas, Andrius; Suttner, Gerald; Tektas, Ozan; Tarkhov, Aleksey; Kornhuber, Johannes; Fromm, Martin F; Bürkle, Thomas; Prokosch, Hans-Ulrich; Maas, Renke

    2016-12-07

    A well-known problem in current clinical decision support systems (CDSS) is the high number of alerts, which are often medically incorrect or irrelevant. This may lead to the so-called alert fatigue, an overriding of alerts, including those that are clinically relevant, and underuse of CDSS in general. The aim of our study was to develop and to apply a standardized tool that allows its users to evaluate the quality of system-generated drug alerts. The users' ratings can subsequently be used to derive recommendations for developing a filter function to reduce irrelevant alerts. We developed a rating tool for drug alerts and performed a web-based evaluation study that also included a user review of alerts. In this study the following categories were evaluated: "data linked correctly", "medically correct", "action required", "medication change", "critical alert", "information gained" and "show again". For this purpose, 20 anonymized clinical cases were randomly selected and displayed in our customized CDSS research prototype, which used the summary of product characteristics (SPC) for alert generation. All the alerts that were provided were evaluated by 13 physicians. The users' ratings were used to derive a filtering algorithm to reduce overalerting. In total, our CDSS research prototype generated 399 alerts. In 98 % of all alerts, medication data were rated as linked correctly to drug information; in 93 %, the alerts were assessed as "medically correct"; 19.5 % of all alerts were rated as "show again". The interrater-agreement was, on average, 68.4 %. After the application of our filtering algorithm, the rate of alerts that should be shown again decreased to 14.8 %. The new standardized rating tool supports a standardized feedback of user-perceived clinical relevance of CDSS alerts. Overall, the results indicated that physicians may consider the majority of alerts formally correct but clinically irrelevant and override them. Filtering may help to reduce

  12. LISA telescope spacer design investigations

    Science.gov (United States)

    Sanjuan, Josep; Mueller, Guido; Livas, Jeffrey; Preston, Alix; Arsenovic, Petar; Castellucci, Kevin; Generie, Joseph; Howard, Joseph; Stebbins, Robin

    The Laser Interferometer Space Antenna (LISA) is a space-based gravitational wave observa-tory with the goal of observing Gravitational Waves (GWs) from astronomical sources in a frequency range from 30 µHz to 0.1 Hz. The detection of GWs at such low frequency requires measurements of distances at the pico-meter level between bodies separated by 5 million kilo-meters. The LISA mission consists of three identical spacecraft (SC) separated by 5 × 106 km forming an equilateral triangle. Each SC contains two optical assemblies and two vacuum en-closures housing one proof mass (PM) in geodesic (free fall) motion each. The two assemblies on one SC are each pointing towards an identical assembly on each of the other two SC to form a non-equal arm interferometer. The measurement of the GW strain is done by measuring the change in the length of the optical path between the PMs of one arm relative to the other arms caused by the pass of a GW. An important element of the Interferometric Measurement System (IMS) is the telescope which, on one hand, gathers the light coming from the far SC (˜100 pW) and, on the other hand, expands and collimates the small outgoing beam ( 1 W) and sends it to the far SC. Due to the very demanding sensitivity requirements care must be taken in the design and validation of the telescope not to degrade the IMS performance. For instance, the diameter of the telescope sets the the shot noise of the IMS and depends critically on the diameter of the primary and the divergence angle of the outgoing beam. As the telescope is rather fast telescope, the divergence angle is a critical function of the overall separation between the primary and secondary. Any long term changes of the distance of more than a a few micro-meter would be detrimental to the LISA mission. Similarly challenging are the requirements on the in-band path-length noise for the telescope which has to be kept below 1 pm Hz-1/2 in the LISA band. Different configurations (on-axis/off axis

  13. The Large Space Telescope program.

    Science.gov (United States)

    O'Dell, C. R.

    1972-01-01

    The 1980's should see the establishment of the first major observatory in space. This observatory will contain a long-lifetime reflecting telescope of about 120 inches clear aperture. Advantages of an orbiting telescope include the elimination of astronomical seeing effects and improvements in resolving power. The small images and darker sky will permit low-dispersion spectrographs to avoid more of the contaminating background. The crispness of the images also has potential for very efficient high-dispersion spectroscopy. A further advantage lies in the accessibility of all the sky and nearly around-the-clock observing.

  14. Superconductor lunar telescopes --Abstract only

    Science.gov (United States)

    Chen, P. C.; Pitts, R.; Shore, S.; Oliversen, R.; Stolarik, J.; Segal, K.; Hojaji, H.

    1994-01-01

    We propose a new type of telescope designed specifically for the lunar environment of high vacuum and low temperature. Large area UV-Visible-IR telescope arrays can be built with ultra-light-weight replica optics. High T(sub c) superconductors provide support, steering, and positioning. Advantages of this approach are light-weight payload compatible with existing launch vehicles, configurable large area optical arrays, no excavation or heavy construction, and frictionless electronically controlled mechanisms. We have built a prototype and will be demonstarting some of its working characteristics.

  15. Heuristic burst detection method using flow and pressure measurements

    NARCIS (Netherlands)

    Bakker, M.; Vreeburg, J.H.G.; Roer, Van de M.; Rietveld, L.C.

    2014-01-01

    Pipe bursts in a drinking water distribution system lead to water losses, interruption of supply, and damage to streets and houses due to the uncontrolled water flow. To minimize the negative consequences of pipe bursts, an early detection is necessary. This paper describes a heuristic burst

  16. Detecting Pipe Bursts Using Heuristic and CUSUM Methods

    NARCIS (Netherlands)

    Bakker, M.; Jung, D.; Vreeburg, J.; Van de Roer, M.; Lansey, K.; Rierveld, L.

    2014-01-01

    Pipe bursts in a drinking water distribution system lead to water losses, interruption of supply, and damage to streets and houses due to the uncontrolled water flow. To minimize the negative consequences of pipe bursts, an early detection is necessary. This paper describes a heuristic burst

  17. IGR J17254-3257, a new bursting neutron star

    DEFF Research Database (Denmark)

    Chenevez, Jérôme; Falanga, M.; Kuulkers, E.

    2007-01-01

    Aims. The study of the observational properties of uncommonly long bursts from low luminosity sources is important when investigating the transition from a hydrogen - rich bursting regime to a pure helium regime and from helium burning to carbon burning as predicted by current burst theories. On ...

  18. ShakeAlert Users Transition to the Production Prototype System

    Science.gov (United States)

    Strauss, J. A.; Vinci, M.; Steele, W. P.; Hellweg, M.; Allen, R. M.; DeGroot, R. M.

    2016-12-01

    The ShakeAlert Earthquake Early Warning system transitioned from the demonstration system into the fully-fledged production prototype system this year. Users were migrated over to the new system concurrent with the release of the ShakeAlert UserDisplay Version 2.5.0. The production prototype system provides robust connectivity, fail-over mechanisms to ensure that alarms are deliverd even if one connection fails, and provides a framework to connect future stations, participants, and other sources as the project expands to the full public system. We will present an overview of key user sectors that are either testing or launching pilot projects for the system within their organizations. We will outline the implementation of certain actions, and highlight accomplishments and challenges the Beta Users encounter in fully implementing ShakeAlert within their organizations. By better studying these issues, project partners can better assist the users in incorporating early warning in their operations. Opening up the system to allow for pilot projects enables ShakeAlert users to develop hardware, software, and policy solutions for actions in response to early warning alerts in a controlled environment. This is the first step on the path toward limited rollouts. The pilot groups leverage the expertise of our stakeholders to develop the `last mile' alert distribution and responses. The transition went smoothly in February 2015, for users in California, and we expect to connect with more beta users and pilot groups in this next phase. User transition is planned for Fall 2016 for users in the Pacific Northwest. Beta Users, such as municipalities, emergency response groups, and county officials, lifelines, schools, and private industry continue to meet with ShakeAlert partners to 1) further education and training on both benefits and limitations 2) strategize on implementation actions, such as opening fire house bay doors in response to an alarm, and 3) coordinate continued

  19. Path correlation considered prioritized burst segmentation for quality of service support in optical burst switching networks

    Science.gov (United States)

    Hou, Rui; Changyue, Jiana; He, Tingting; Yu, Jianwei; Lei, Bo; Mao, Tengyue

    2013-04-01

    Burst segmentation (BS) is a high-efficiency contention resolution scheme in bufferless optical burst switching (OBS) networks. A prioritized BS scheme for quality of service (QoS) support is developed. Unlike the existing work on the BS scheme, the proposed BS model considers path-correlated factors, such as path length, the adjoining paths carrying traffic on a given path, and the multipriority traffic coming from all paths. Byte loss probability for high-priority and low-priority bursts under the time-based assembly approach and the length-based assembly approach to estimate the performance of the proposed BS scheme by comparing the cumulative distribution function of a burst length in an OBS ingress node (source) with that in an egress node (destination) is introduced. A preemptive BS policy for different priority bursts is proposed to support the QoS of the OBS network. Finally, a simulation is given to validate the proposed analytical model in an existing OBS network with two priority bursts. It is shown that the proposed BS scheme can realize the service differentiation for multipriority traffic under the consideration of network topology-dependent parameters.

  20. Hα Intensity Map of the Repeating Fast Radio Burst FRB 121102 Host Galaxy from Subaru/Kyoto 3DII AO-assisted Optical Integral-field Spectroscopy

    Science.gov (United States)

    Kokubo, Mitsuru; Mitsuda, Kazuma; Sugai, Hajime; Ozaki, Shinobu; Minowa, Yosuke; Hattori, Takashi; Hayano, Yutaka; Matsubayashi, Kazuya; Shimono, Atsushi; Sako, Shigeyuki; Doi, Mamoru

    2017-08-01

    We present the Hα intensity map of the host galaxy of the repeating fast radio burst FRB 121102 at a redshift of z = 0.193 obtained with the AO-assisted Kyoto 3DII optical integral-field unit mounted on the 8.2 m Subaru Telescope. We detected a compact Hα-emitting (I.e., star-forming) region in the galaxy, which has a much smaller angular size (universe as {{{Ω }}}{IGM}> 0.012. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  1. In-Flight Calibrations of UFFO-Pathfinder

    DEFF Research Database (Denmark)

    Řípa, J.; Ahmad, S.; Barrillon, P.

    2013-01-01

    The Ultra-Fast Flash Observatory (UFFO), which will be launched onboard the Lomonosov spacecraft, contains two crucial instruments: UFFO Burst Alert & Trigger Telescope (UBAT) for detection and localization of Gamma-Ray Bursts (GRBs) and the fast-response Slewing Mirror Telescope (SMT) designed f...

  2. The Fermi-GBM X-Ray Burst Monitor: Thermonuclear Bursts from 4U 0614+09

    NARCIS (Netherlands)

    Linares, M.; Connaughton, V.; Jenke, P.; van der Horst, A.J.; Camero-Arranz, A.; Kouveliotou, C.; Chakrabarty, D.; Beklen, E.; Bhat, P.N.; Briggs, M.S.; Finger, M.; Paciesas, W.S.; Preece, R.; von Kienlin, A.; Wilson-Hodge, C.A.

    2012-01-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi

  3. Testing and modelling of the SVOM MXT narrow field lobster-eye telescope

    Science.gov (United States)

    Feldman, Charlotte; Pearson, James; Willingale, Richard; Sykes, John; Drumm, Paul; Houghton, Paul; Bicknell, Chris; Osborne, Julian; Martindale, Adrian; O'Brien, Paul; Fairbend, Ray; Schyns, Emile; Petit, Sylvain; Roudot, Romain; Mercier, Karine; Le Duigou, Jean-Michel; Gotz, Diego

    2017-08-01

    The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a French-Chinese space mission to be launched in 2021 with the goal of studying gamma-ray bursts, the most powerful stellar explosions in the Universe. The Microchannel X-ray Telescope (MXT) on-board SVOM, is an X-ray focusing telescope with a detector-limited field of view of ˜1 square° , working in the 0.2-10 keV energy band. The MXT is a narrow-field-optimised lobster eye telescope, designed to promptly detect and accurately locate gamma-ray bursts afterglows. The breadboard MXT optic comprises of an array of square pore micro pore optics (MPOs) which are slumped to a spherical radius of 2 m giving a focal length of 1 m and an intrinsic field of view of ˜6° . We present details of the baseline design and results from the ongoing X-ray tests of the breadboard and structural thermal model MPOs performed at the University of Leicester and at Panter. In addition, we present details of modelling and analysis which reveals the factors that limit the angular resolution, characteristics of the point spread function and the efficiency and collecting area of the currently available MPOs.

  4. X-Ray Polarization Measurements with the EXIST Hard X-Ray Survey Telescope

    Science.gov (United States)

    Krawczynski, Henric; Garson, A., III; Hong, J.; Grindlay, J. E.

    2009-01-01

    The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed NASA mission for scanning the entire sky in intermediate and hard X-rays. The EXIST mission includes a wide field of view High Energy Telescope (HET) covering the 5-600 keV energy range, and an infrared telescope. The HET has the capability to measure the energy dependent X-ray polarization properties of moderately bright and bright X-ray sources. Here we report on a study of the polarization sensitivity of EXIST as a function of the integration time. Broadband X-ray polarization measurements with EXIST have the potential to make important contributions to our understanding of a number of astrophysical source types including binary black holes, accreting neutron stars, magnetars, pulsar wind nebulae, active galactic nuclei and gamma-ray bursts. EXIST observations of the X-rays from binary black holes can be used to constrain the spins of black holes. Last but not least, EXIST observations of active galactic nuclei and gamma-ray bursts can be used for extremely sensitive Lorentz Invariance tests.

  5. Optimizing The Imaging Performance Of The Exist High Energy Telescope

    Science.gov (United States)

    Skinner, Gerald K.; Finger, M. H.; Hong, J.; Jernigan, J. G.; Sturner, S. J.; Allen, B.; Grindlay, J. E.

    2009-01-01

    The baseline concept for the primary instrument of the EXIST mission, the high energy telescope (HET), is a coded mask instrument with a wide field of view and extremely good sensitivity (Hong et al., this meeting). Achieving the performance goals requires an imaging capability close to the statistical photon limit, minimizing systematic errors even when the total integration time is very long. At the same time there is a requirement to be able to reconstruct images on board in near real time in order to detect and localize gamma-ray bursts. This must be done while the spacecraft is scanning the sky with a motion designed to help reduce systematic errors and to provide all-sky coverage. During the 2008 Advanced Mission Concept Study, the Exist Imaging Technical Working Group has investigated and compared numerous alternative designs for the HET. The selected baseline concept meets all of the scientific requirements, while being compatible with spacecraft and launch constraints and with those imposed by the Infra-Red Telescope that forms the other key part of the mission. The approach adopted depends on a unique annular coded mask with two spatial scales, offering good resolution and low background at low energies, with a lower resolution but enhanced sensitivity in the upper part of the energy band. Monte Carlo simulations and analytic analysis techniques have been used to demonstrate the capabilities of the proposed design.

  6. The origins of the telescope

    NARCIS (Netherlands)

    van Helden, A.|info:eu-repo/dai/nl/072210524; Dupré, S.|info:eu-repo/dai/nl/23478055X; van Gent, R.; Zuidervaart, H.J.

    2011-01-01

    The origins of the telescope have been debated since the instrument’s appearance in the Hague in 1608. Civic and national pride has led local dignitaries, popular writers, and scholars to present sharply divergent histories over the years, crediting a variety of people and places with the invention.

  7. Monster telescope hunts blue planets

    CERN Multimedia

    Leake, J

    2003-01-01

    BRITAIN is to back a project to build the world's biggest telescope - so powerful that it could see life-bearing planets in other solar systems. It will need the largest mirror ever built at about 100 metres in diameter (1/2 page).

  8. INTERPLANETARY NETWORK LOCALIZATIONS OF KONUS SHORT GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Pal' shin, V. D.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Oleynik, P. P.; Ulanov, M. V. [Ioffe Physical Technical Institute, St. Petersburg, 194021 (Russian Federation); Hurley, K. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Cline, T.; Trombka, J.; McClanahan, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Boynton, W.; Fellows, C.; Harshman, K., E-mail: val@mail.ioffe.ru [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States); and others

    2013-08-15

    Between the launch of the Global Geospace Science Wind spacecraft in 1994 November and the end of 2010, the Konus-Wind experiment detected 296 short-duration gamma-ray bursts (including 23 bursts which can be classified as short bursts with extended emission). During this period, the Interplanetary Network (IPN) consisted of up to 11 spacecraft, and using triangulation, the localizations of 271 bursts were obtained. We present the most comprehensive IPN localization data on these events. The short burst detection rate, {approx}18 yr{sup -1}, exceeds that of many individual experiments.

  9. Emergency Communications: The Emergency Alert System (EAS) and All-Hazard Warnings

    Science.gov (United States)

    2005-09-02

    Communications: The Emergency Alert System (EAS) and All- Hazard Warnings Updated September 2, 2005 Linda K. Moore Analyst in Telecommunications Policy...3. DATES COVERED - 4. TITLE AND SUBTITLE Emergency Communications: The Emergency Alert System (EAS) and All- Hazard Warnings 5a. CONTRACT... Emergency Alert System (EAS) and All- Hazard Warnings Summary The Emergency Alert System (EAS) is one of several federally managed warning systems. The

  10. Overdenture dengan Pegangan Telescopic Crown

    Directory of Open Access Journals (Sweden)

    Pambudi Santoso

    2014-06-01

    Full Text Available Kaitan presisi merupakan alat retensi mekanis yang menghubungkan antara satu atau lebih pegangan gigi tiruan, yang bertujuan untuk menambah retensi dan/atau stabilisasi. Kaitan presisi dapat digunakan secara luas pada gigi tiruan cekat, gigi tiruan sebagian lepasan, overdenture, implant untuk retensi overdenture, dan protesa maksilo fasial. Overdenture dengan kaitan presisi dapat membantu dalam pembagian beban kunyah, meminimalkan trauma pada gigi pegangan dan jaringan lunak, meminimalkan resorbsi tulang, dan meningkatkan estetik dan pengucapan suara. Salah satu jenis dari kaitan presisi adalah telescopic crown, terdiri dari 2 macam mahkota, yaitu mahkota primer yang melekat secara permanen pada gigi penyangga, dan mahkota sekunder yang melekat pada gigi tiruan. Tujuan pemaparan kasus ini adalah untuk memberikan informasi tentang rehabilitasi pasien edentulous sebagian rahang atas dengan telescopic crown..  Pasien wanita berusia 45 tahun datang ke klinik prostodonsia RSGM Prof.Soedomo dengan keluhan ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 11 12 15 16 17 21 22 24 25 26 dan 27 yang diindikasikan untuk pembuatan overdenture gigi tiruan sebagian lepasan (GTS kerangka logam dengan pegangan telescopic crown pada gigi 13 dan 14 dengan sistem parallel-sided crown. Tahap-tahap pembuatan telescopic crown yaitu mencetak model study dengan catatan gigit pendahuluan. Perawatan saluran dilakukan pada akar gigi 13, dilanjutkan pemasangan pasak fiber serta rewalling dinding bukal. Gigi 13 dan 14 dilakukan preparasi mahkota penuh, dilanjutkan dengan pencetakan model kerja untuk coping primer dan kerangka logam dengan metode double impression. Coping primer disementasi pada gigi penyangga, dilanjutkan pasang coba coping sekunder beserta kerangka logam. Selanjutnya dilakukan pencatatan gigit, pencetakan model kerja, penyusunan gigi dan pasang coba penyusunan gigi pada pasien. Prosedur dilanjutkan dengan proses di laboratorium, serta insersi pada

  11. NEAT: A Microarcsec Astrometric Telescope

    Science.gov (United States)

    Shao, M.; Nemati, B.; Zhai, C.; Goullioud, R.

    2011-01-01

    NEAT, Nearby Exo-Earth Astrometric Telescope is a medium-small telescope (is) approximately 1m in diameter that is designed to make ultra precise (is) less than 1 uas (microarcsec) astrometric measurements of nearby stars in a (is) approximately 1hr observation. Four major error sources prevent normal space telescopes from obtaining accuracies close to 1 uas. Even with a small 1m telescope, photon noise is usually not a problem for the bright nearby target stars. But in general, the reference stars are much fainter. Typically a field of view of (is) approximately 0.5 deg dia is needed to obtain enough bright reference stars. The NEAT concept uses a very simple but unusual design to avoid optically induced astrometric errors. The third source of error is the accuracy and stability of the focal plane. A 1uas error over a (is) approximately 2000 arcsec field of view implies the focal plane is accurate or at least stable to 5 parts in 10(exp 10) over the lifetime of the mission ( (is) approximately 5yrs). The 4th class of error has to do with our knowledge of the PSF and how that PSF is sampled by an imperfect detector. A Nyquist sampled focal plane would have (is) greater than 2 pixels per lambda/D, and centroiding to 1uas means centroiding to 10-5 pixels. This paper describes the mission concept, and an overview of the technology needed to perform 1uas astrometry with a small telescope, and how we overcome problems 1 and 2. A companion paper will describe the technical progress we've made in solving problems 3 and 4.

  12. 75 FR 26269 - Draft Programmatic Environmental Assessment for the Integrated Public Alert and Warning Program's...

    Science.gov (United States)

    2010-05-11

    ... Public Alert and Warning Program's Construction Projects AGENCY: Federal Emergency Management Agency, DHS... Public Alert and Warning Program (IPAWS). The construction actions will be taken to ensure that FEMA meets its responsibilities under Executive Order 13407, Public Alert and Warning System, by providing...

  13. Method and apparatus for extraction of low-frequency artifacts from brain waves for alertness detection

    Science.gov (United States)

    Clapp, Ned E.; Hively, Lee M.

    1997-01-01

    Methods and apparatus automatically detect alertness in humans by monitoring and analyzing brain wave signals. Steps include: acquiring the brain wave (EEG or MEG) data from the subject, digitizing the data, separating artifact data from raw data, and comparing trends in f-data to alertness indicators, providing notification of inadequate alertness.

  14. Discriminating between true-positive and false-positive clinical mastitis alerts from automatic milking systems

    NARCIS (Netherlands)

    Steeneveld, W.; Gaag, van der L.C.; Ouweltjes, W.; Mollenhorst, H.; Hogeveen, H.

    2010-01-01

    Automatic milking systems (AMS) generate alert lists reporting cows likely to have clinical mastitis (CM). Dutch farmers indicated that they use non-AMS cow information or the detailed alert information from the AMS to decide whether to check an alerted cow for CM. However, it is not yet known to

  15. The redshift and afterglow of the extremely energetic gamma-ray burst GRB 080916C

    CERN Document Server

    Greiner, J.; Kruehler, T.; Kienlin, A.v.; Rau, A.; Sari, R.; Fox, Derek B.; Kawai, N.; Afonso, P.; Ajello, M.; Berger, E.; Cenko, S.B.; Cucchiara, A.; Filgas, R.; Klose, S.; Yoldas, A.Kuepue; Lichti, G.G.; Loew, S.; McBreen, S.; Nagayama, T.; Rossi, A.; Sato, S.; Szokoly, G.; Yoldas, A.; Zhang, X.-L.

    2009-01-01

    The detection of GeV photons from gamma-ray bursts (GRBs) has important consequences for the interpretation and modelling of these most-energetic cosmological explosions. The full exploitation of the high-energy measurements relies, however, on the accurate knowledge of the distance to the events. Here we report on the discovery of the afterglow and subsequent redshift determination of GRB 080916C, the first GRB detected by the Fermi Gamma-Ray Space Telescope with high significance detection of photons at >0.1 GeV. Observations were done with 7-channel imager GROND at the 2.2m MPI/ESO telescope, the SIRIUS instrument at the Nagoya-SAAO 1.4m telescope in South Africa, and the GMOS instrument at Gemini-S. The afterglow photometric redshift of z=4.35+-0.15, based on simultaneous 7-filter observations with the Gamma-Ray Optical and Near-infrared Detector (GROND), places GRB 080916C among the top 5% most distant GRBs, and makes it the most energetic GRB known to date. The detection of GeV photons from such a dista...

  16. A burst in a wind bubble and the impact on baryonic ejecta: high-energy gamma-ray flashes and afterglows from fast radio bursts and pulsar-driven supernova remnants

    Science.gov (United States)

    Murase, Kohta; Kashiyama, Kazumi; Mészáros, Peter

    2016-09-01

    Tenuous wind bubbles, which are formed by the spin-down activity of central compact remnants, are relevant in some models of fast radio bursts (FRBs) and superluminous supernovae (SNe). We study their high-energy signatures, focusing on the role of pair-enriched bubbles produced by young magnetars, rapidly rotating neutron stars, and magnetized white dwarfs. (i) First, we study the nebular properties and the conditions allowing for escape of high-energy gamma-rays and radio waves, showing that their escape is possible for nebulae with ages of ≳10-100 yr. In the rapidly rotating neutron star scenario, we find that radio emission from the quasi-steady nebula itself may be bright enough to be detected especially at sub-mm frequencies, which is relevant as a possible counterpart of pulsar-driven SNe and FRBs. (ii) Secondly, we consider the fate of bursting emission in the nebulae. We suggest that an impulsive burst may lead to a highly relativistic flow, which would interact with the nebula. If the shocked nebula is still relativistic, pre-existing non-thermal particles in the nebula can be significantly boosted by the forward shock, leading to short-duration (maybe millisecond or longer) high-energy gamma-ray flashes. Possible dissipation at the reverse shock may also lead to gamma-ray emission. (iii) After such flares, interactions with the baryonic ejecta may lead to afterglow emission with a duration of days to weeks. In the magnetar scenario, this burst-in-bubble model leads to the expectation that nearby (≲10-100 Mpc) high-energy gamma-ray flashes may be detected by the High-Altitude Water Cherenkov Observatory and the Cherenkov Telescope Array, and the subsequent afterglow emission may be seen by radio telescopes such as the Very Large Array. (iv) Finally, we discuss several implications specific to FRBs, including constraints on the emission regions and limits on soft gamma-ray counterparts.

  17. A simple model of burst nucleation.

    Science.gov (United States)

    Baronov, Alexandr; Bufkin, Kevin; Shaw, Dan W; Johnson, Brad L; Patrick, David L

    2015-08-28

    We introduce a comprehensive quantitative treatment for burst nucleation (BN)-a kinetic pathway toward self-assembly or crystallization defined by an extended post-supersaturation induction period, followed by a burst of nucleation, and finally the growth of existing stable assemblages absent the formation of new ones-based on a hybrid mean field rate equation model incorporating thermodynamic treatment of the saturated solvent from classical nucleation theory. A key element is the inclusion of a concentration-dependent critical nucleus size, determined self-consistently along with the subcritical cluster population density. The model is applied to an example experimental study of crystallization in tetracene films prepared by organic vapor-liquid-solid deposition, where good agreement is observed with several aspects of the experiment using a single, physically well-defined adjustable parameter. The model predicts many important features of the experiment, and can be generalized to describe other self-organizing systems exhibiting BN kinetics.

  18. New approach to rock burst forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, V.V.; Fokin, A.N.; Pimonov, A.G. (Kuzbasskii Politekhnicheskii Institut (USSR))

    1990-10-01

    Deals with the problem of rock burst forecasting that departs from the concept of solid body strength and breaking and from equations that relate endurance of a solid body to continuous stress. A formula is derived that permits the lifetime of a rock volume under stress to be calculated. A block diagram of a laboratory automatic system is presented that is capable of monitoring the stress state of a rock sample and of forecasting the time to sample destruction. The system consists of a loading fixture, electromagnetic emission sensor, frequency meter, microprocessor and plotter. An example of a plot of the rate of fissure formation as a function of time is shown and a monitor screen display of a sample life versus time is also presented. It is maintained that the system creates a basis for developing a system that would monitor and forecast rock burst hazards in a continuous manner. 4 refs.

  19. A review of gamma ray bursts

    CERN Document Server

    Rees, Martin J

    2000-01-01

    Gamma-ray bursts, an enigma for more than 25 years, are now coming into focus. They involve extraordinary power outputs, and highly relativistic dynamics. The 'trigger' involves stellar-mass compact objects. The most plausible progenitors, ranging from neutron star binary mergers to collapsars (sometimes called 'hypernovae') eventually lead to the formation of a black hole with a torus of hot neutron-density material around it, the extractable energy being up to 10 sup 5 sup 4 ergs. Magnetic fields may exceed 10 sup 1 sup 5 G and particles may be accelerated up to > or approx. 10 sup 2 sup 0 eV. Details of the afterglow may be easier to understand than the initial trigger. Bursts at very high redshift can be astronomically-important as probes of the distant universe.

  20. Coherent combining pulse bursts in time domain

    Energy Technology Data Exchange (ETDEWEB)

    Galvanauskas, Almantas

    2018-01-09

    A beam combining and pulse stacking technique is provided that enhances laser pulse energy by coherent stacking pulse bursts (i.e. non-periodic pulsed signals) in time domain. This energy enhancement is achieved by using various configurations of Fabry-Perot, Gires-Tournois and other types of resonant cavities, so that a multiple-pulse burst incident at either a single input or multiple inputs of the system produces an output with a solitary pulse, which contains the summed energy of the incident multiple pulses from all beams. This disclosure provides a substantial improvement over conventional coherent-combining methods in that it achieves very high pulse energies using a relatively small number of combined laser systems, thus providing with orders of magnitude reduction in system size, complexity, and cost compared to current combining approaches.

  1. Numerical simulations of trailing vortex bursting

    Science.gov (United States)

    Beran, Philip S.

    1987-01-01

    Solutions of the steady-state Navier-Stokes equations for the axisymmetric bursting of a laminar trailing vortex are computed with Newton's method and the pseudo-arc length continuation method for wide ranges of vortex strength and Reynolds number. The results indicate that a trailing vortex can undergo a transition from a state in which the core slowly diffuses to a state marked by large amplitude, spatial oscillations of core radius and core axial velocity. At the transition point the core grows rapidly in size. This event is interpreted as vortex bursting. The results also suggest that when the maximum core swirl velocity is sufficiently large the centerline axial flow downstream of transition will be reversed.

  2. Bursting of sensitive polymersomes induced by curling.

    Science.gov (United States)

    Mabrouk, Elyes; Cuvelier, Damien; Brochard-Wyart, Françoise; Nassoy, Pierre; Li, Min-Hui

    2009-05-05

    Polymersomes, which are stable and robust vesicles made of block copolymer amphiphiles, are good candidates for drug carriers or micro/nanoreactors. Polymer chemistry enables almost unlimited molecular design of responsive polymersomes whose degradation upon environmental changes has been used for the slow release of active species. Here, we propose a strategy to remotely trigger instantaneous polymersome bursting. We have designed asymmetric polymer vesicles, in which only one leaflet is composed of responsive polymers. In particular, this approach has been successfully achieved by using a UV-sensitive liquid-crystalline copolymer. We study experimentally and theoretically this bursting mechanism and show that it results from a spontaneous curvature of the membrane induced by the remote stimulus. The versatility of this mechanism should broaden the range of applications of polymersomes in fields such as drug delivery, cosmetics and material chemistry.

  3. Art concept of the Hubble Space Telescope

    Science.gov (United States)

    1986-01-01

    Art concept of the Hubble Space Telescope in orbit above the earth with a Space Shuttle approaching and an astronaut performing an extravehicular activity (EVA) (30462); Art concept of the Hubble Space Telescope with the interior design exposed (30463).

  4. The cannonball model of gamma ray bursts

    CERN Document Server

    Dar, Arnon

    2003-01-01

    The cannonball model (CB) of gamma ray bursts (GRBs) is incredibly more successful than the standard blast-wave models (SM) of GRBs, which suffer from profound inadequacies and limited predictive power. The CB model is falsifiable in its hypothesis and results. Its predictions are summarized in simple analytical expressions, derived, in fair approximations, from first principles. It provides a good description on a universal basis of the properties of long-duration GRBs and of their afterglows (AGs).

  5. Automatic Cloud Bursting under FermiCloud

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao [Fermilab; Shangping, Ren [IIT; Garzoglio, Gabriele [Fermilab; Timm, Steven [Fermilab; Bernabeu, Gerard [Fermilab; Kim, Hyun Woo; Chadwick, Keith; Jang, Haengjin [KISTI, Daejeon; Noh, Seo-Young [KISTI, Daejeon

    2013-01-01

    Cloud computing is changing the infrastructure upon which scientific computing depends from supercomputers and distributed computing clusters to a more elastic cloud-based structure. The service-oriented focus and elasticity of clouds can not only facilitate technology needs of emerging business but also shorten response time and reduce operational costs of traditional scientific applications. Fermi National Accelerator Laboratory (Fermilab) is currently in the process of building its own private cloud, FermiCloud, which allows the existing grid infrastructure to use dynamically provisioned resources on FermiCloud to accommodate increased but dynamic computation demand from scientists in the domains of High Energy Physics (HEP) and other research areas. Cloud infrastructure also allows to increase a private cloud’s resource capacity through “bursting” by borrowing or renting resources from other community or commercial clouds when needed. This paper introduces a joint project on building a cloud federation to support HEP applications between Fermi National Accelerator Laboratory and Korea Institution of Science and Technology Information, with technical contributions from the Illinois Institute of Technology. In particular, this paper presents two recent accomplishments of the joint project: (a) cloud bursting automation and (b) load balancer. Automatic cloud bursting allows computer resources to be dynamically reconfigured to meet users’ demands. The load balance algorithm which the cloud bursting depends on decides when and where new resources need to be allocated. Our preliminary prototyping and experiments have shown promising success, yet, they also have opened new challenges to be studied

  6. Black Hole Accretion in Gamma Ray Bursts

    Directory of Open Access Journals (Sweden)

    Agnieszka Janiuk

    2017-02-01

    Full Text Available We study the structure and evolution of the hyperaccreting disks and outflows in the gamma ray bursts central engines. The torus around a stellar mass black hole is composed of free nucleons, Helium, electron-positron pairs, and is cooled by neutrino emission. Accretion of matter powers the relativistic jets, responsible for the gamma ray prompt emission. The significant number density of neutrons in the disk and outflowing material will cause subsequent formation of heavier nuclei. We study the process of nucleosynthesis and its possible observational consequences. We also apply our scenario to the recent observation of the gravitational wave signal, detected on 14 September 2015 by the two Advanced LIGO detectors, and related to an inspiral and merger of a binary black hole system. A gamma ray burst that could possibly be related with the GW150914 event was observed by the Fermi satellite. It had a duration of about 1 s and appeared about 0.4 s after the gravitational-wave signal. We propose that a collapsing massive star and a black hole in a close binary could lead to the event. The gamma ray burst was powered by a weak neutrino flux produced in the star remnant’s matter. Low spin and kick velocity of the merged black hole are reproduced in our simulations. Coincident gravitational-wave emission originates from the merger of the collapsed core and the companion black hole.

  7. Management options in thoracolumbar burst fractures.

    Science.gov (United States)

    Hitchon, P W; Torner, J C; Haddad, S F; Follett, K A

    1998-06-01

    Both surgery and recumbency have been adopted in the treatment of spinal fractures. Herein we present the indications for each, and our experience with thoracolumbar junction (T12, L1 and L2) burst fractures. Sixty-eight patients with thoracolumbar burst fractures were treated operatively in 36 cases, and nonoperatively in 32 with recumbency for 1-6 weeks. Treatment was based on clinical and radiological criteria. Eighty-one percent of the recumbency patients, but only 14% of the surgical patients were intact on admission. Patients were followed for a mean+/-SD of 9+/-10 months in the recumbency group, and 21+/-21 months in the surgical group. Neurological improvement and progressive angular deformity occurred in both groups. The cost of recumbency in our patients was nearly half that of those who required surgery, though the length of hospitalization between the two groups was similar at 1 month +/-2 weeks. The above study emphasizes that the selection of operative versus nonoperative treatment in burst fractures should not be random but based on clinical as well as radiological criteria. Recumbency is favored in patients who are intact, with angular deformity less than 20 degrees , a residual spinal canal greater than 50% of normal, and an anterior body height exceeding 50% of the posterior height. Surgical intervention is generally indicated in patients with partial neurological deficit, and those with severe instability.

  8. RADIO FLARES FROM GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom); Harrison, R. [Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Japelj, J.; Gomboc, A. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Guidorzi, C. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy); Melandri, A., E-mail: D.Kopac@ljmu.ac.uk [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807, Merate (Italy)

    2015-06-20

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  9. Secured Hash Based Burst Header Authentication Design for Optical Burst Switched Networks

    Science.gov (United States)

    Balamurugan, A. M.; Sivasubramanian, A.; Parvathavarthini, B.

    2017-12-01

    The optical burst switching (OBS) is a promising technology that could meet the fast growing network demand. They are featured with the ability to meet the bandwidth requirement of applications that demand intensive bandwidth. OBS proves to be a satisfactory technology to tackle the huge bandwidth constraints, but suffers from security vulnerabilities. The objective of this proposed work is to design a faster and efficient burst header authentication algorithm for core nodes. There are two important key features in this work, viz., header encryption and authentication. Since the burst header is an important in optical burst switched network, it has to be encrypted; otherwise it is be prone to attack. The proposed MD5&RC4-4S based burst header authentication algorithm runs 20.75 ns faster than the conventional algorithms. The modification suggested in the proposed RC4-4S algorithm gives a better security and solves the correlation problems between the publicly known outputs during key generation phase. The modified MD5 recommended in this work provides 7.81 % better avalanche effect than the conventional algorithm. The device utilization result also shows the suitability of the proposed algorithm for header authentication in real time applications.

  10. Content Aware Burst Assembly - Supporting Telesurgery and Telemedicine in Optical Burst Switching Networks

    Directory of Open Access Journals (Sweden)

    Henry Orosco

    2010-08-01

    Full Text Available The emerging Telemedicine and Telesurgery technologies allow patients to share medical experts remotely through communication networks. However, network bandwidth, network latency and jitter (variation of latency, are the obstacles to the widespread use of this technology remotely. Optical Burst Switching (OBS networks greatly expand network bandwidth in existing network infrastructure by utilizing multiple DWDM channels within a single fiber, enabling high bandwidth applications. However, the burst assembly process in OBS networks introduces latency and jitter, making it unsuitable for high bandwidth, latency sensitive applications such as telesurgery and telemedicine. In this paper, we propose a content aware burst assembly scheme which dynamically adjusts the burst assembly parameters based on the content being assembled. The proposed content aware burst assembly minimizes the latency and jitter within a video frame, as well as across the left-view and right-view frames for 3D vision generation. Simulation results have shown that the proposed scheme can effectively reduce the latency and jitter experienced by video streams, making OBS a promising candidate for supporting telesurgery and telemedicine applications.

  11. The Next Generation Space Telescope

    Science.gov (United States)

    Bely, Pierre-Yves (Editor); Burrows,, Christopher J. (Editor); Illingworth,, Garth D.

    1989-01-01

    In Space Science in the Twenty-First Century, the Space Science Board of the National Research Council identified high-resolution-interferometry and high-throughput instruments as the imperative new initiatives for NASA in astronomy for the two decades spanning 1995 to 2015. In the optical range, the study recommended an 8 to 16-meter space telescope, destined to be the successor of the Hubble Space Telescope (HST), and to complement the ground-based 8 to 10-meter-class telescopes presently under construction. It might seem too early to start planning for a successor to HST. In fact, we are late. The lead time for such major missions is typically 25 years, and HST has been in the making even longer with its inception dating back to the early 1960s. The maturity of space technology and a more substantial technological base may lead to a shorter time scale for the development of the Next Generation Space Telescope (NGST). Optimistically, one could therefore anticipate that NGST be flown as early as 2010. On the other hand, the planned lifetime of HST is 15 years. So, even under the best circumstances, there will be a five year gap between the end of HST and the start of NGST. The purpose of this first workshop dedicated to NGST was to survey its scientific potential and technical challenges. The three-day meeting brought together 130 astronomers and engineers from government, industry and universities. Participants explored the technologies needed for building and operating the observatory, reviewed the current status and future prospects for astronomical instrumentation, and discussed the launch and space support capabilities likely to be available in the next decade. To focus discussion, the invited speakers were asked to base their presentations on two nominal concepts, a 10-meter telescope in space in high earth orbit, and a 16-meter telescope on the moon. The workshop closed with a panel discussion focused mainly on the scientific case, siting, and the

  12. Reduction in alert fatigue in an assisted electronic prescribing system, through the Lean Six Sigma methodology.

    Science.gov (United States)

    Cuéllar Monreal, Mª Jesús; Reig Aguado, Jorge; Font Noguera, Isabel; Poveda Andrés, José Luis

    2017-01-01

    To reduce the alert fatigue in our Assisted Electronic Prescribing System (AEPS), through the Lean Six Sigma (LSS) methodology. An observational (transversal) and retrospective study, in a general hospital with 850 beds and AEPS. The LSS methodology was followed in order to evaluate the alert fatigue situation in the AEPS system, to implement improvements, and to assess outcomes. The alerts generated during two trimesters studied (before and after the intervention) were analyzed. In order to measure the qualitative indicators, the most frequent alert types were analyzed, as well as the molecules responsible for over 50% of each type of alert. The action by the prescriber was analyzed in a sample of 496 prescriptions that generated such alerts. For each type of alert and molecule, there was a prioritization of the improvements to be implemented according to the alert generated and its quality. A second survey evaluated the pharmacist action for the alerts most highly valued by physicians. The problem, the objective, the work team and the project schedule were defined. A survey was designed in order to understand the opinion of the client about the alert system in the program. Based on the surveys collected (n = 136), the critical characteristics and the quanti/qualitative indicators were defined. Sixty (60) fields in the alert system were modified, corresponding to 32 molecules, and this led to a 28% reduction in the total number of alerts. Regarding quality indicators, false po sitive results were reduced by 25% (p < 0.05), 100% of those alerts ignored with justification were sustained, and there were no significant differences in user adherence to the system. The project improvements and outcomes were reviewed by the work team. LSS methodology has demonstrated being a valid tool for the quantitative and qualitative improvement of the alert system in an Assisted Electronic Prescription Program, thus reducing alert fatigue. Copyright AULA MEDICA EDICIONES 2014

  13. CHIME and probing the origin of fast radio bursts

    Science.gov (United States)

    Connor, Liam Dean

    The time-variable long-wavelength sky harbours a number of known but unsolved astrophysical problems, and surely many more undiscovered phenomena. With modern tools such problems will become tractable, and new classes of astronomical objects will be revealed. These tools include digital telescopes made from powerful computing clusters, and improved theoretical methods. In this thesis we employ such devices to understand better several puzzles in the time-domain radio sky. Our primary focus is on the origin of fast radio bursts (FRBs), a new class of transients of which there seem to be thousands per sky per day. We offer a model in which FRBs are extragalactic but non-cosmological pulsars in young supernova remnants. Since this theoretical work was done, observations have corroborated the picture of FRBs as young rotating neutron stars, including the non-Poissonian repetition of FRB 121102. We also present statistical arguments regarding the nature and location of FRBs. These include reinstituting the classic V/Vmax-test to measure the brightness distribution of FRBs, i.e., constraining ∂log N/∂log S. We find consistency with a Euclidean distribution. This means current observations cannot distinguish between a cosmological population and a more local uniform population, unless added assumptions are made. We also showed that the rate of FRBs at low frequencies is consistent with the rate at 1.4 GHz, which is promising for upcoming high-impact experiments. One of these is the Canadian Hydrogen Intensity Mapping Experiment (CHIME). We outline this instrument and its three back-ends: a cosmology experiment whose goal is to measure dark energy through 21 cm intensity mapping, a pulsar back-end, and an FRB project that is expected to be by far the fastest survey in the foreseeable future. We describe the creation of a digital beamforming back-end on the CHIME Pathfinder, which acts as a test-bed for the three final experiments just described. We also discuss the

  14. CFRP lightweight structures for extremely large telescopes

    DEFF Research Database (Denmark)

    Jessen, Niels Christian; Nørgaard-Nielsen, Hans Ulrik; Schroll, J.

    2008-01-01

    Telescope structures are traditionally built out of steel. To improve the possibility of realizing the ambitious extremely large telescopes, materials with a higher specific stiffness and a lower coefficient of thermal expansion are needed. An important possibility is Carbon Fibre Reinforced Plas...... Plastic (CFRP). The advantages of using CFRP for the secondary mirror support structure of the European overwhelmingly large telescope are discussed....

  15. The Hubble Space Telescope: Problems and Solutions.

    Science.gov (United States)

    Villard, Ray

    1990-01-01

    Presented is the best understanding of the flaw discovered in the optics of the Hubble Space Telescope and the possible solutions to the problems. The spherical aberration in the telescope's mirror and its effect on the quality of the telescope's imaging ability is discussed. (CW)

  16. The Principles of Astronomical Telescope Design

    CERN Document Server

    Cheng, Jingquan

    2009-01-01

    Presents a summary of the author's twenty five years of experience in telescope design. This work provides a general introduction to various aspects of telescope design. It discusses the theory behind telescope design. It covers Radio, Infrared, Optical, X-Ray and Gamma-Ray wavelengths

  17. Distributions of solar drift-pair bursts in frequency from decameter radio observations

    Science.gov (United States)

    Stanislavsky, Aleksander; Volvach, Yaroslav

    2017-04-01

    Statement of the Problem: Solar drift-pair (DP) bursts are one of interesting manifestations of solar activity. Observed during the solar storms of type III bursts, they demonstrate a very simple form on dynamic radio spectra as two short components separated in time, often the second component being the full repetition of the first. As is well known, type III bursts are produced by the accelerated electrons propagating along open magnetic field lines in solar corona. However, no each storm of type III bursts leads to any DP. The role of electron beams in the generation of DPs remains unclear. Solar DPs are detected by ground-based instruments at decameter and meter wavelengths, but each individual DP occupies only a limited bandwidth in the frequency range. The bursts drift in frequency, and their frequency drift rate can be both negative and positive (so-called the forward and reverse DPs), from -2 MHz/s to 6 MHz/s [1]. Besides, there are cases of vertical DPs, which occur simultaneously in all the frequencies within their bandwidth. It is difficult to interpret them by means of a moving source, as any exciting agent responsible for such bursts would travel with velocities faster than velocity of light [2]. Methodology & Experimental Orientation: New features of modern low-frequency radio astronomy allow us to study the empirical properties of DPs more deeply than ever before. Our results are based on the recent radio data (during 10-12 July of 2015) obtained with help of the UTR-2 radio telescope at frequencies 9-33 MHz with the time resolution of 50 ms and the frequency resolution of 4 kHz. We have identified 301 DP bursts in which 209 events were forward (FDP), and the rest were reverse (RDP). Results & Significance: According to the data, the occurrence of FDPs decreased at high frequencies, whereas the number of RDPs had an opposite tendency, they rarely occured at lower frequencies. During the observational session, at 20-25 MHz almost the same amount of

  18. A deep-learning-based emergency alert system

    Directory of Open Access Journals (Sweden)

    Byungseok Kang

    2016-06-01

    Full Text Available Emergency alert systems serve as a critical link in the chain of crisis communication, and they are essential to minimize loss during emergencies. Acts of terrorism and violence, chemical spills, amber alerts, nuclear facility problems, weather-related emergencies, flu pandemics, and other emergencies all require those responsible such as government officials, building managers, and university administrators to be able to quickly and reliably distribute emergency information to the public. This paper presents our design of a deep-learning-based emergency warning system. The proposed system is considered suitable for application in existing infrastructure such as closed-circuit television and other monitoring devices. The experimental results show that in most cases, our system immediately detects emergencies such as car accidents and natural disasters.

  19. SC-228 Inclusion of DAA Warning Alert for TCAS Interoperability

    Science.gov (United States)

    Fern, Lisa

    2016-01-01

    This white paper summarizes NASA research results that have informed Special Committee 228 (SC-228) discussions and decisions regarding the inclusion of a warning-level alert within the detect and avoid (DAA) alerting structure for unmanned aircraft systems (UAS). For UAS, the removal of the pilot from onboard the aircraft has eliminated the ability of the ground-based pilot in command (PIC) to use out-the-window visual information to make judgments about a potential threat of a loss of well clear with another aircraft. As a result, the DAA traffic display will be the primary source of information that the PIC can use to execute the three primary well clear functions: 1) detect a potential loss of well clear, 2) determine a resolution maneuver, and 3) upload that maneuver to the aircraft via the ground control station (GCS). In addition, pilots are required to coordinate with air traffic control (ATC) prior to maneuvering off of their approved flight plan. In determining an appropriate resolution maneuver to avoid a loss of well clear, the PIC must decide both when and how to maneuver, and both the timeliness and the accuracy (i.e., correctness) of the maneuver are critical to reducing the likelihood and/or severity of a loss of well clear. Alerting information is one of three critical components of the DAA display, along with traffic information elements (e.g., relative heading, speed and altitude) and maneuver guidance. Alerting information and maneuver guidance, in particular, have been found to have a significant impact, both statistically and practically, on pilots' ability to avoid and minimize the severity of losses of well clear While all three display components are key to pilots performing the traffic avoidance task of remaining well clear, in general, alerting information provides crucial information about when a resolution maneuver is required while maneuver guidance assists the pilot in determining how best to maneuver. A fundamental task of the DAA

  20. Evaluation of otoacoustic emissions in clinically normal alert puppies.

    Science.gov (United States)

    Schemera, Bettina; Blumsack, Judith T; Cellino, Alice F; Quiller, Travis D; Hess, Bradley A; Rynders, Patricia E

    2011-03-01

    To evaluate distortion product otoacoustic emission (DPOAE) measurements in puppies with normal hearing. 23 clinically normal 7.5-to 10.5-week-old puppies. A cross-sectional study was performed. The DPOAE measurements were obtained with a commercially available distortion product otoacoustic measurement system and were performed in a quiet, non-sound-attenuated room. All measurements were obtained from alert puppies and were repeated 1 or 2 times to ensure that the measurements were replicable. Results that were a minimum of 8 dB higher than the noise floor were accepted. Values from the first trial in which emissions were obtained at all test frequencies were used for analysis. Otoacoustic emission measurements were easily obtained, robust, reliable, and consistent with auditory brainstem response and behavioral results. Hearing screening in alert puppies can be accomplished reliably and rapidly with otoacoustic emissions testing. Results supported the possibility of the use of DPOAE measurement in hearing screening of dogs.

  1. 21 Cataclysmic variables to be observed by William Herschel Telescope

    Science.gov (United States)

    Waagen, Elizabeth O.

    2016-12-01

    Roque Ruiz-Carmona (Ph.D. candidate, Institute of Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen, The Netherlands) has requested AAVSO assistance with his campaign to observe a set of 21 cataclysmic variables (CVs) with the William Herschel Telescope (WHT) at La Palma on 2016 December 16. This campaign is essentially identical in format to the ones successfully carried out by the AAVSO on his behalf in 2015 and in May 2016 (AAVSO Alert Notices 524, 527, 543). Ruiz-Carmona writes: "As the end of my PhD is closer now, this is the second-to-last campaign monitoring CVs into outburst. As an update on my research, it seems that unexpectedly spiral density waves can only be detectable in high inclination systems and it seems that the luminosity of the disk in outburst outshines the spiral pattern for the rest of the system. This can also have deep implications: it can be that the spiral density waves are only an effect of the atmospheres of the disks and are therefore unrelated to transport of matter and angular momentum in the disks. In order to investigate this hypothesis, the sample of CVs I would like to monitor contains only eclipsing systems."[As before,] I just need to know if the targets are in outburst or not..." The PI has requested AAVSO observers to obtain one image of each target on each of TWO separate nights so he may analyze them to determine the final observing list for WHT. Links to finder charts as well as reporting instructions and other information may be found in the full Alert Notice.

  2. Traffic Alert and Collision Avoidance System. Developmental Simulation.

    Science.gov (United States)

    1982-07-01

    display (CRT) could lead to pilot complacency with insufficient visual scan time beinq devoted to nontransponder- equinned aircraft. The data indicates...CHAIN CONTROLLERJ VOICE/TONE SP AKf r 3 BIT PARALLEL FOR AIRCRAFT WARNINC REMOTE AND CAUTION ALERTS LED TCAS DISPLAY J.NIT COMPUTER WARNING CONTROL AND...FNGINEiAERO CAUTION NOISE 16- BIT HOST AUDIO- CONTROL OF VISUAL ATC SPEAKER SYSTEM SYSTEM J AUDIOVISUALS Figure A.2-1. CAS Sinilation Ecji’pment Layout

  3. Simulation and Proposed Handover Alert Algorithm for Mobile Communication System

    OpenAIRE

    Muzhir Shaban Al-Ani; Wael Hassan Al-Sawalmeh

    2009-01-01

    this paper deals with the simulation and presentation of a novel approach to design and implementation of algorithm to realize hand over process for a mobile communication system during mobile network. This algorithm performs the ability of the system to extract important information features about the received signal. When the strength of the received signal is dropped below a certain threshold value then an alert process is activated to achieve the continuity of the transmission due to a re...

  4. Clinical decision support alert malfunctions: analysis and empirically derived taxonomy.

    Science.gov (United States)

    Wright, Adam; Ai, Angela; Ash, Joan; Wiesen, Jane F; Hickman, Thu-Trang T; Aaron, Skye; McEvoy, Dustin; Borkowsky, Shane; Dissanayake, Pavithra I; Embi, Peter; Galanter, William; Harper, Jeremy; Kassakian, Steve Z; Ramoni, Rachel; Schreiber, Richard; Sirajuddin, Anwar; Bates, David W; Sittig, Dean F

    2017-10-16

    To develop an empirically derived taxonomy of clinical decision support (CDS) alert malfunctions. We identified CDS alert malfunctions using a mix of qualitative and quantitative methods: (1) site visits with interviews of chief medical informatics officers, CDS developers, clinical leaders, and CDS end users; (2) surveys of chief medical informatics officers; (3) analysis of CDS firing rates; and (4) analysis of CDS overrides. We used a multi-round, manual, iterative card sort to develop a multi-axial, empirically derived taxonomy of CDS malfunctions. We analyzed 68 CDS alert malfunction cases from 14 sites across the United States with diverse electronic health record systems. Four primary axes emerged: the cause of the malfunction, its mode of discovery, when it began, and how it affected rule firing. Build errors, conceptualization errors, and the introduction of new concepts or terms were the most frequent causes. User reports were the predominant mode of discovery. Many malfunctions within our database caused rules to fire for patients for whom they should not have (false positives), but the reverse (false negatives) was also common. Across organizations and electronic health record systems, similar malfunction patterns recurred. Challenges included updates to code sets and values, software issues at the time of system upgrades, difficulties with migration of CDS content between computing environments, and the challenge of correctly conceptualizing and building CDS. CDS alert malfunctions are frequent. The empirically derived taxonomy formalizes the common recurring issues that cause these malfunctions, helping CDS developers anticipate and prevent CDS malfunctions before they occur or detect and resolve them expediently.

  5. Design of a probabilistic wildfire alert system for Chile

    Science.gov (United States)

    Crawford, Ben; Dacre, Helen; Lopez Saldana, Gerardo; Charlton-Perez, Andrew

    2017-04-01

    During the past 50 years over 200,000 wildfires have burned nearly 2.3 million hectares in Chile, leading to significant economic consequences. To improve wildfire warning capabilities, statistical models have been developed by the University of Chile for 15 different geographic regions of the country to quantify wildfire risk based on a set of specific meteorological variables (air temperature, relative humidity, wind speed, accumulated precipitation, and time of year). Currently, the warning system uses data input from ground-based weather stations and alerts are issued one day ahead. This project improves upon the current system by using variables from ensemble weather prediction datasets (TIGGE archive from ECMWF) as input to the wildfire risk model. This allows development of a probabilistic alert system that takes into account uncertainties in the specific meteorological forecast variables used in the wildfire risk model. This also allows the wildfire risk index to be calculated up to seven days ahead. The integration of the statistical wildfire risk model with the ensemble weather prediction system provides additional information about uncertainty to improve resource allocation decisions. The new system is evaluated using MODIS satellite wildfire detection datasets from 2008-2015 for each of the 15 geographic wildfire risk regions. The prototype alert system is then compared to alerts made using forecast variables from the operational ensemble weather prediction system used by the Chilean Meteorological Service. Finally, a novel method to update the wildfire risk statistical model parameters in real time based on observed spatial and temporal wildfire patterns will be presented.

  6. Red Alert: Marxist Approaches to Science Fiction Cinema

    OpenAIRE

    Mazierska, Ewa Hanna; Suppia, Alfredo

    2016-01-01

    In Red Alert: Marxist Approaches to Science Fiction Cinema, editors Ewa Mazierska and Alfredo Suppia argue that Marxist philosophy, science fiction, and film share important connections concerning imaginings of the future. Contributors look at themes across a wide variety of films, including many international co-productions to explore individualism versus collectivism, technological obstacles to travel through time and space, the accumulation of capital and colonization, struggles of oppress...

  7. Study of Integration Considerations for Wireless Emergency Alerts

    Science.gov (United States)

    2014-02-01

    ComLabs • Digital Alert Systems • Emergency Communications Network • ESi Acquisition, Inc. • Everbridge • Eye Street Solutions • NC4...could lighten the load on the networks. For example, rather than overloading voice and data cellular networks with cell phone calls and searches...1:39 pm Several bystanders near the smoke complain of burning eyes and lungs. 8 1:52 pm Firefighters are able to deploy at the accident and start to

  8. Traffic Alert and Collision Avoidance System - Operational Simulation.

    Science.gov (United States)

    1985-03-01

    alert was used to tell the crew that they were not in difficulty at that point (IVSI needle was out of the lights) and they should use care to see that...TCAS evaluation. Care must be used when interpreting the performance results because of the nature of the study. Even though the pilots were informed...and Robinson, J. E., Mid-Air Collision Avoidance with Navigational Light Systems, Applied Psycology Corporation for Airways Modernization Board

  9. Addressing Inpatient Glycaemic Control with an Inpatient Glucometry Alert System

    Directory of Open Access Journals (Sweden)

    J. N. Seheult

    2015-01-01

    Full Text Available Background. Poor inpatient glycaemic control has a prevalence exceeding 30% and results in increased length of stay and higher rates of hospital complications and inpatient mortality. The aim of this study was to improve inpatient glycaemic control by developing an alert system to process point-of-care blood glucose (POC-BG results. Methods. Microsoft Excel Macros were developed for the processing of daily glucometry data downloaded from the Cobas IT database. Alerts were generated according to ward location for any value less than 4 mmol/L (hypoglycaemia or greater than 15 mmol/L (moderate-severe hyperglycaemia. The Diabetes Team provided a weekday consult service for patients flagged on the daily reports. This system was implemented for a 60-day period. Results. There was a statistically significant 20% reduction in the percentage of hyperglycaemic patient-day weighted values >15 mmol/L compared to the preimplementation period without a significant change in the percentage of hypoglycaemic values. The time-to-next-reading after a dysglycaemic POC-BG result was reduced by 14% and the time-to-normalization of a dysglycaemic result was reduced from 10.2 hours to 8.4 hours. Conclusion. The alert system reduced the percentage of hyperglycaemic patient-day weighted glucose values and the time-to-normalization of blood glucose.

  10. Addressing Inpatient Glycaemic Control with an Inpatient Glucometry Alert System.

    Science.gov (United States)

    Seheult, J N; Pazderska, A; Gaffney, P; Fogarty, J; Sherlock, M; Gibney, J; Boran, G

    2015-01-01

    Background. Poor inpatient glycaemic control has a prevalence exceeding 30% and results in increased length of stay and higher rates of hospital complications and inpatient mortality. The aim of this study was to improve inpatient glycaemic control by developing an alert system to process point-of-care blood glucose (POC-BG) results. Methods. Microsoft Excel Macros were developed for the processing of daily glucometry data downloaded from the Cobas IT database. Alerts were generated according to ward location for any value less than 4 mmol/L (hypoglycaemia) or greater than 15 mmol/L (moderate-severe hyperglycaemia). The Diabetes Team provided a weekday consult service for patients flagged on the daily reports. This system was implemented for a 60-day period. Results. There was a statistically significant 20% reduction in the percentage of hyperglycaemic patient-day weighted values >15 mmol/L compared to the preimplementation period without a significant change in the percentage of hypoglycaemic values. The time-to-next-reading after a dysglycaemic POC-BG result was reduced by 14% and the time-to-normalization of a dysglycaemic result was reduced from 10.2 hours to 8.4 hours. Conclusion. The alert system reduced the percentage of hyperglycaemic patient-day weighted glucose values and the time-to-normalization of blood glucose.

  11. [Impact of media alerts on contraceptive pills medication].

    Science.gov (United States)

    Pozzi-Gaudin, S; Deffieux, X; Davitian, C; Guerre, N; Faucher, P; Bacle, F; Teboul, M; Larmignat, P; Hatchuel, M; Benachi, A

    2015-09-01

    The end of 2012 was marked by some media alerts regarding combined hormonal contraceptives (CHC) and lawsuit against pharmaceutical companies selling these birth control pills. In this study, we analyzed whether these information had an impact on the number of abortion. Prospective study determining the number of women asking for abortion and who spontaneously declare that the contraception defect was due to an abandon of their oral contraception as they were scared of some information they received from media about the medication. Eleven centers out of 16 did participate to the study, allowing the study of 2300 abortion during this time frame. Ninety-eight of these pregnancies (4.2%) were due to an interruption of the contraceptive treatment as a consequence of media alerts. Average age was 26 years old. Within these pregnancies, 4 (6%) started in December 2012, 3 months after the beginning of the alerts, 11 (16%) in January, 24 (36%) in February and 18 (27%) in March 2013 (4-6 months later). In 7 cases (10%) CHC stopped by fear of information reported by media were of 2nd generation, in 17 cases (25%) of 3rd generation, in 32 cases (48%) of 4th generation and microprogestative in 2 cases (3%). Women who declared that they stopped their birth control medication by fear of information reported in media, represented 4% of the number of abortions performed between 2013 February 18th and 2013 April 30th. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  12. AN AUTOMATED NETWORK SECURITYCHECKING AND ALERT SYSTEM: A NEW FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Vivek Kumar Yadav

    2013-09-01

    Full Text Available Network security checking is a vital process to assess and to identify weaknesses in network for management of security. Insecure entry points of a network provide attackers an easy target to access and compromise. Open ports of network components such as firewalls, gateways and end systems are analogues to open gates of a building through which any one can get into. Network scanning is performed to identify insecure entry points in the network components. To find out vulnerabilities on these points vulnerability assessment is performed. So security checking consists of both activities- network scanning as well as vulnerability assessment. A single tool used for the security checking may not give reliable results. This paper presents a framework for assessing the security of a network using multiple Network Scanning and Vulnerability Assessment tools. The proposed framework is an extension of the framework given by Jun Yoon and Wontae Sim [1] which performs vulnerability scanning only. The framework presented here adds network scanning, alerting and reporting system to their framework. Network scanning and vulnerability tools together complement each other and make it amenable for centralized control and management. The reporting system of framework sends an email to the network administrator which contains detailed report (as attachment of security checking process. Alerting system sends a SMS message as an alert to the network administrator in case of severe threats found in the network. Initial results of the framework are encouraging and further work is in progress.

  13. IP telephony based danger alert communication system and its implementation

    Science.gov (United States)

    Rezac, Filip; Safarik, Jakub; Voznak, Miroslav; Tomala, Karel; Partila, Pavol

    2013-05-01

    This article discusses a danger alert system created as a part of the research project at Department of Telecommunications of Technical University of Ostrava. The aim of the system is to distribute pre-recorded voice messages in order to alert the called party in danger. This article describes individual technologies, which the application uses for its operation as well as issues relating to hardware requirements and transfer line bandwidth load. The article also describes new algorithms, which had to be developed in order to ensure the reliability of the system. Our intent is focused on disaster management, the message, which should be delivered within specified time span, is typed in the application and text-to-speech module ensures its transformation to a speech format, after that a particular scenario or warned area is selected and a target group is automatically unloaded. For this purpose, we have defined XML format for delivery of phone numbers which are located in the target area and these numbers are obtained from mobile BTS's (Base transmission stations). The benefit of such communication compared to others, is the fact, that it uses a phone call and, therefore, it is possible to get feedback who accepted the message and to improve efficiency of alert system. Finally, the list of unanswered calls is exported and these users can be informed via SMS.

  14. Generic Model to Send Secure Alerts for Utility Companies

    Directory of Open Access Journals (Sweden)

    Perez–Díaz J.A.

    2010-04-01

    Full Text Available In some industries such as logistics services, bank services, and others, the use of automated systems that deliver critical business information anytime and anywhere play an important role in the decision making process. This paper introduces a "Generic model to send secure alerts and notifications", which operates as a middleware between enterprise data sources and its mobile users. This model uses Short Message Service (SMS as its main mobile messaging technology, however is open to use new types of messaging technologies. Our model is interoperable with existing information systems, it can store any kind of information about alerts or notifications at different levels of granularity, it offers different types of notifications (as analert when critical business problems occur,asanotificationina periodical basis or as 2 way query. Notification rules can be customized by final users according to their preferences. The model provides a security framework in the cases where information requires confidentiality, it is extensible to existing and new messaging technologies (like e–mail, MMS, etc. It is a platform, mobile operator and hardware independent. Currently, our solution is being used at the Comisión Federal de Electricidad (Mexico's utility company to deliver secure alerts related to critical events registered in the main power generation plants of our country.

  15. Determination of Dark Energy by the Einstein Telescope: Comparing with CMB, BAO and SNIa Observations

    OpenAIRE

    Zhao, W.; Broeck, C. Van Den; Baskaran, D.; Li, T. G. F.

    2010-01-01

    A design study is currently in progress for a third generation gravitational-wave (GW) detector called Einstein Telescope (ET). An important kind of source for ET will be the inspiral and merger of binary neutron stars (BNS) up to $z \\sim 2$. If BNS mergers are the progenitors of short-hard $\\gamma$-ray bursts, then some fraction of them will be seen both electromagnetically and through GW, so that the luminosity distance and the redshift of the source can be determined separately. An importa...

  16. Slewing mirror telescope of the UFFO-pathfinder: first report on performance in space

    DEFF Research Database (Denmark)

    Gaikov, G.; Jeong, S.; Agaradahalli, V. G.

    2017-01-01

    To observe the early optical emissions from gamma ray bursts (GRBs), we built the Slew Mirror Telescope. It utilizes a 150 mm motorized mirror to redirect incoming photons from astrophysical objects within seconds and to track them as compensating satellite movements. The SMT is a major component...... of the UFFO-pathfinder payload, which was launched on April 28, 2016, onboard the Lomonosov satellite. For the first time, the slewing mirror system has been proven for the precision tracking of astrophysical objects during space operation. We confirmed that the SMT has 1.4 seconds of response time to the X...

  17. Focusing Telescopes in Nuclear Astrophysics

    CERN Document Server

    Ballmoos, Peter von

    2007-01-01

    This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference

  18. Study of Solar-Terrestrial Connections in the Highlight of Simultaneous Observations with STEREO and UTR-2, URAN, NDA Ground-Based Radio Telescopes

    Science.gov (United States)

    Melnik, V. N.; Rucker, H. O.; Konovalenko, A. A.; Lecacheux, A.; Falkovich, I. S.

    In the present paper new opportunities, which will be appeared at simultaneous observations by STEREO and ground-based radio telescopes (UTR-2, URAN, NDA), in study of solar sporadic phenomena, having essential effects on the Earth, are discussed. CMEs, which manifest themselves in radio emission as Type II and Type IY bursts, are the most important of them. Studying of these bursts during simultaneous observations with the help of STEREO and ground-based radio telescopes will allow to find the direction of CME movement, 3D images of CME, its beaming pattern, bulk energy of both CME and shock before it, particle acceleration sites and directions of propagation of accelerated particles. Analyses of radio observations of active and quiet Sun will allow to understand pre-CME conditions in the solar corona and will give an opportunity to forecast CME appearance. Observations of different types of sporadic radio emissions (Type III bursts, drift pairs, s-bursts, bursts in absorption etc.) with high sensitivity, high frequency and time resolutions in decameter range by ground-based radio telescopes and detection of regions, where this radio emission goes out from (using STEREO results), will allow to diagnose the coronal plasmas (to define their density, magnetic fields, parameters of inhomogenieties) at altitudes 0.5-2Rs and to build adequate model of CME formation and its evolution. Using of interplanetary scintillation methods tested on UTR-2 and URAN radio telescope as well as in situ measurements on STEREO will give the information about both CME structure and shock associated with it, about spectra of density fluctuations and turbulences connected with CME at distances about 1a.u. from the Sun.

  19. Diffractive X-ray Telescopes

    OpenAIRE

    Skinner, Gerald K

    2010-01-01

    Diffractive X-ray telescopes using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution several orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted space- time in the immediate vicinity of the super...

  20. Burst-suppression is reactive to photic stimulation in comatose children with acquired brain injury

    DEFF Research Database (Denmark)

    Nita, Dragos A.; Moldovan, Mihai; Sharma, Roy

    2016-01-01

    Objective: Burst-suppression is an electroencephalographic pattern observed during coma. In individuals without known brain pathologies undergoing deep general anesthesia, somatosensory stimulation transiently increases the occurrence of bursts. We investigated the reactivity of burst-suppression......Objective: Burst-suppression is an electroencephalographic pattern observed during coma. In individuals without known brain pathologies undergoing deep general anesthesia, somatosensory stimulation transiently increases the occurrence of bursts. We investigated the reactivity of burst...... reactivity. We quantified reactivity by measuring the change in the burst ratio (fraction of time in burst) following photic stimulation. Results: Photic stimulation evoked bursts in all patients, resulting in a transient increase in the burst ratio, while the mean heart rate remained unchanged....... The regression slope of the change in burst ratio, referred to as the standardized burst ratio reactivity, correlated with subjects' Glasgow Coma Scale scores. Conclusions: Reactivity of the burst-suppression pattern to photic stimulation occurs across diverse coma etiologies. Standardized burst ratio reactivity...

  1. Dynamic encoding of natural luminance sequences by LGN bursts.

    Directory of Open Access Journals (Sweden)

    Nicholas A Lesica

    2006-07-01

    Full Text Available In the lateral geniculate nucleus (LGN of the thalamus, visual stimulation produces two distinct types of responses known as tonic and burst. Due to the dynamics of the T-type Ca(2+ channels involved in burst generation, the type of response evoked by a particular stimulus depends on the resting membrane potential, which is controlled by a network of modulatory connections from other brain areas. In this study, we use simulated responses to natural scene movies to describe how modulatory and stimulus-driven changes in LGN membrane potential interact to determine the luminance sequences that trigger burst responses. We find that at low resting potentials, when the T channels are de-inactivated and bursts are relatively frequent, an excitatory stimulus transient alone is sufficient to evoke a burst. However, to evoke a burst at high resting potentials, when the T channels are inactivated and bursts are relatively rare, prolonged inhibitory stimulation followed by an excitatory transient is required. We also observe evidence of these effects in vivo, where analysis of experimental recordings demonstrates that the luminance sequences that trigger bursts can vary dramatically with the overall burst percentage of the response. To characterize the functional consequences of the effects of resting potential on burst generation, we simulate LGN responses to different luminance sequences at a range of resting potentials with and without a mechanism for generating bursts. Using analysis based on signal detection theory, we show that bursts enhance detection of specific luminance sequences, ranging from the onset of excitatory sequences at low resting potentials to the offset of inhibitory sequences at high resting potentials. These results suggest a dynamic role for burst responses during visual processing that may change according to behavioral state.

  2. Type III Radio Burst Duration and SEP Events

    Science.gov (United States)

    Gopalswamy, N.; Makela, P.; Xie, H.

    2010-01-01

    Long-duration (>15 min), low-frequency (SEP events of solar cycle 23. The Type III durations are distributed symmetrically at 1 MHz yielding a mean value of approximately 33 min (median = 32 min) for the large SEP events. When the SEP events with ground level enhancement (GLE,) are considered, the distribution is essentially unchanged (mean = 32 min, median = 30 min). To test the importance of type III bursts in indicating SEP events, we considered a set of six type III bursts from the same active region (AR 10588) whose durations fit the "long duration" criterion. We analyzed the coronal mass ejections (CMEs), flares, and type II radio bursts associated with the type III bursts. The CMEs were of similar speeds and the flares are also of similar size and duration. All but one of the type III bursts was not associated with a type II burst in the metric or longer wavelength domains. The burst without type II burst also lacked a solar energetic particle (SEP) event at energies >25 MeV. The 1-MHz duration of the type III burst (28 rein) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. This study suggests that the type III burst duration may not be a good indicator of an SEP event, consistent with the statistical study of Cliver and Ling (2009, ApJ ).

  3. The NASA Spitzer Space Telescope.

    Science.gov (United States)

    Gehrz, R D; Roellig, T L; Werner, M W; Fazio, G G; Houck, J R; Low, F J; Rieke, G H; Soifer, B T; Levine, D A; Romana, E A

    2007-01-01

    The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.

  4. Building the Green Bank Telescope

    Science.gov (United States)

    Kellermann, Kenneth I.

    2017-01-01

    In a previous presentation, I reported on how the freak collapse of the NRAO 300-ft transit radio telescope led to the inclusion of $75 million for a new radio telescope in the 1989 Congressional Emergency Supplemental Appropriations Act. But, this was only the beginning. NRAO was faced with challenging specifications and an unworkable schedule, but there was no design and no project team. Only one bid was even close to the Congressional appropriation. In an attempt to meet the unrealistic antenna delivery date, the contractor started construction of the foundation and fabrication of antenna members before the design was finished, leading to retrofits, redesign, and multiple delays. The antenna contractor was twice sold to other companies leading to further delays and cost escalation. In order to recoup their mounting losses, the new owners sued NRAO for $29 million for claimed design changes, and NRAO countersued demanding to be reimbursed for added project management costs and lost scientific data resulting from the seven-year delay in the completion of the telescope. Legal fees and a small net award in favor of the contractor left NRAO and the NSF with a nine million dollar bill which NSF handled by an innovative accounting adjustment.

  5. The NASA Spitzer Space Telescope

    Science.gov (United States)

    Gehrz, R. D.; Roellig, T. L.; Werner, M. W.; Fazio, G. G.; Houck, J. R.; Low, F. J.; Rieke, G. H.; Soifer, B. T.; Levine, D. A.; Romana, E. A.

    2007-01-01

    The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.

  6. Academic Training: Deep Space Telescopes

    CERN Multimedia

    Françoise Benz

    2006-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 20, 21, 22, 23, 24 February from 11:00 to 12:00 - Council Chamber on 20, 21, 23, 24 February, TH Auditorium, bldg 4 - 3-006, on 22 February Deep Space Telescopes G. BIGNAMI / CNRS, Toulouse, F & Univ. di Pavia, I The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo's telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics thro...

  7. Burst segmentation for void-filling scheduling and its performance evaluation in optical burst switching.

    Science.gov (United States)

    Tan, Wei; Wang, Sheng; Li, Lemin

    2004-12-27

    As a promising solution for the next generation optical Internet, optical burst switching still has much to be improved, especially the design of core routers. This paper mainly focuses on channel scheduling algorithms of core routers and proposes a new practical scheduling algorithm. In the new algorithm, burst segmentation, one of the contention resolution schemes that are another major concern in core router design, is introduced. The proposed algorithm is analyzed theoretically and evaluated by computer simulations. The results show that the new algorithm, compared with existing traditional scheduling algorithms, can lower the packet loss probability and enhance the link utilization and network performance.

  8. Observing Pulsars with a Phased Array Feed at the Parkes Telescope

    Science.gov (United States)

    Deng, X.; Chippendale, A. P.; Hobbs, G.; Johnston, S.; Dai, S.; George, D.; Kramer, M.; Karuppusamy, R.; Malenta, M.; Spitler, L.; Tzioumis, T.; Wieching, G.

    2017-07-01

    During 2016 February, CSIRO Astronomy and Space Science and the Max-Planck-Institute for Radio Astronomy installed, commissioned, and carried out science observations with a phased array feed receiver system on the 64-m diameter Parkes radio telescope. Here, we demonstrate that the phased array feed can be used for pulsar observations and we highlight some unique capabilities. We demonstrate that the pulse profiles obtained using the phased array feed can be calibrated and that multiple pulsars can be simultaneously observed. Significantly, we find that an intrinsic polarisation leakage of -31 dB can be achieved with a phased array feed beam offset from the centre of the field of view. We discuss the possibilities for using a phased array feed for future pulsar observations and for searching for fast radio bursts with the Parkes and Effelsberg telescopes.

  9. Fermi Gamma-Ray Space Telescope: Highlights of the GeV Sky

    Science.gov (United States)

    Thomspon, D. J.

    2011-01-01

    Because high-energy gamma rays can be produced by processes that also produce neutrinos. the gamma-ray survey of the sky by the Fermi Gamma-ray Space Telescope offers a view of potenl ial targds for neutrino observations. Gamma-ray bursts. active galactic nuclei, and supernova remnants are all sites where hadronic, neutrino-producing interactions are plausible. Pulsars, pulsar wind nebulae, and binary sources are all phenomena that reveal leptonic particle acceleration through their gamma-ray emission. \\Vhile important to gamma-ray astrophysics. such sources are of less interest to neutrino studies. This talk will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT) on the Fermi spacecraft.

  10. EXIST (Energetic X-ray Imaging Survey Telescope): The Next Large GRB Observatory

    Science.gov (United States)

    Fishman, G. J.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Studies have begun on the EXIST (Energetic X-ray Imaging Survey Telescope) Mission. It is planned as a very wide-field, sensitive coded aperture telescope with a sensitive area of the order of 6-8 m^2 and having a positional accuracy for GRBs (Gamma ray bursts) better than one arc-minute. EXIST will use SWIFT as a pathfinder mission; the findings of SWIFT will refine the scientific objectives of EXIST and will help to determine many of its design parameters. It would study early star formation and early galaxy formation at very high redshifts through observations of thousands of GRBs, their afterglows and environments. It is intended that the international GRB community will play as large role in EXIST through direct participation as well as with complementary observational programs, both space-based and ground-based. Some preliminary design features and capabilities of the EXIST Mission will be presented.

  11. Synchrotron cooling in energetic gamma-ray bursts observed by the Fermi Gamma-Ray Burst Monitor

    Science.gov (United States)

    Yu, Hoi-Fung; Greiner, Jochen; van Eerten, Hendrik; Burgess, J. Michael; Narayana Bhat, P.; Briggs, Michael S.; Connaughton, Valerie; Diehl, Roland; Goldstein, Adam; Gruber, David; Jenke, Peter A.; von Kienlin, Andreas; Kouveliotou, Chryssa; Paciesas, William S.; Pelassa, Véronique; Preece, Robert D.; Roberts, Oliver J.; Zhang, Bin-Bin

    2015-01-01

    Context. We study the time-resolved spectral properties of energetic gamma-ray bursts (GRBs) with good high-energy photon statistics observed by the Gamma-Ray Burst Monitor (GBM) onboard the Fermi Gamma-Ray Space Telescope. Aims: We aim to constrain in detail the spectral properties of GRB prompt emission on a time-resolved basis and to discuss the theoretical implications of the fitting results in the context of various prompt emission models. Methods: Our sample comprises eight GRBs observed by the Fermi GBM in its first five years of mission, with 1 keV-1 MeV fluence f> 1.0 × 10-4 erg cm-2 and a signal-to-noise ratio level of S/N ≥ 10.0 above 900 keV. We performed a time-resolved spectral analysis using a variable temporal binning technique according to optimal S/N criteria, resulting in a total of 299 time-resolved spectra. We performed Band function fits to all spectra and obtained the distributions for the low-energy power-law index α, the high-energy power-law index β, the peak energy in the observed νFν spectrum Ep, and the difference between the low- and high-energy power-law indices Δs = α - β. We also applied a physically motivated synchrotron model, which is a triple power-law with constrained power-law indices and a blackbody component, to test the prompt emission for consistency with a synchrotron origin and obtain the distributions for the two break energies Eb,1 and Eb,2, the middle segment power-law index β, and the Planck function temperature kT. Results: The Band function parameter distributions are α = -0.73+0.16-0.21, β =ي-2.13+0.28-0.56, Ep = 374.4+307.3-187.7 , , keV (log10Ep = 2.57+0.26-0.30), and Δs = 1.38+0.54-0.31 , with average errors σα ~ 0.1, σβ ~ 0.2, and σEp ~ 0.1Ep. Using the distributions of Δs and β, the electron population index p is found to be consistent with the "moderately fast" scenario, in which fast- and slow-cooling scenarios cannot be distinguished. The physically motivated synchrotron

  12. Very Long Baseline Interferometry Experiment on Giant Radio Pulses of Crab Pulsar toward Fast Radio Burst Detection

    Science.gov (United States)

    Takefuji, K.; Terasawa, T.; Kondo, T.; Mikami, R.; Takeuchi, H.; Misawa, H.; Tsuchiya, F.; Kita, H.; Sekido, M.

    2016-08-01

    We report on a very long baseline interferometry (VLBI) experiment on giant radio pulses (GPs) from the Crab pulsar in the radio 1.4-1.7 GHz range to demonstrate a VLBI technique for searching for fast radio bursts (FRBs). We carried out the experiment on 2014 July 26 using the Kashima 34 m and Usuda 64 m radio telescopes of the Japanese VLBI Network (JVN) with a baseline of about 200 km. During the approximately 1 hr observation, we could detect 35 GPs by high-time-resolution VLBI. Moreover, we determined the dispersion measure (DM) to be 56.7585 ± 0.0025 on the basis of the mean DM of the 35 GPs detected by VLBI. We confirmed that the sensitivity of a detection of GPs using our technique is superior to that of a single-dish mode detection using the same telescope.

  13. Time to Detection with BacT/Alert FA Plus Compared to BacT/Alert FA Blood Culture Media.

    Science.gov (United States)

    Nutman, A; Fisher Even-Tsur, S; Shapiro, G; Braun, T; Schwartz, D; Carmeli, Y

    2016-09-01

    Rapid identification of the causative pathogen in patients with bacteremia allows adjustment of antibiotic therapy and improves patient outcomes. We compared in vitro and real-life time to detection (TTD) of two blood culture media, BacT/Alert FA (FA) and BacT/Alert FA Plus (FA Plus), for the nine most common species of bacterial pathogens recovered from blood samples. Experimental data from simulated cultures was compared with microbiology records of TTD for both culture media with growth of the species of interest in clinical blood cultures. In the experimental conditions, median TTD was 3.8 hours (23.9 %) shorter using FA Plus media. The magnitude of reduction differed between species. Similarly, in real life data, FA Plus had shorter TTD than FA media; however, the difference between culture media was smaller, and median TTD was only 1 hour (8.5 %) less. We found shorter TTD with BacT/Alert FA Plus culture media, both experimentally and in real-life conditions and unrelated to antibiotic neutralization, highlighting the importance of appropriate blood culture media selection.

  14. Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert?

    Directory of Open Access Journals (Sweden)

    Sarah Laxhmi Chellappa

    Full Text Available BACKGROUND: Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance. METHODS: Sixteen healthy young men were studied in a balanced cross-over design with light exposure of 3 different light settings (compact fluorescent lamps with light of 40 lux at 6500K and at 2500K and incandescent lamps of 40 lux at 3000K during 2 h in the evening. RESULTS: Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task, but not in tasks associated with executive function (Paced Visual Serial Addition Task. This cognitive improvement was strongly related with attenuated salivary melatonin levels, particularly for the light condition at 6500K. CONCLUSIONS: Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.

  15. Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert?

    Science.gov (United States)

    Chellappa, Sarah Laxhmi; Steiner, Roland; Blattner, Peter; Oelhafen, Peter; Götz, Thomas; Cajochen, Christian

    2011-01-26

    Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance. Sixteen healthy young men were studied in a balanced cross-over design with light exposure of 3 different light settings (compact fluorescent lamps with light of 40 lux at 6500K and at 2500K and incandescent lamps of 40 lux at 3000K) during 2 h in the evening. Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task), but not in tasks associated with executive function (Paced Visual Serial Addition Task). This cognitive improvement was strongly related with attenuated salivary melatonin levels, particularly for the light condition at 6500K. Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.

  16. Obscura telescope with a MEMS micromirror array for space observation of transient luminous phenomena or fast-moving objects.

    Science.gov (United States)

    Park, J H; Garipov, G K; Jeon, J A; Khrenov, B A; Kim, J E; Kim, M; Kim, Y K; Lee, C-H; Lee, J; Na, G W; Nam, S; Park, I H; Park, Y-S

    2008-12-08

    We introduce a novel telescope consisting of a pinhole-like camera with rotatable MEMS micromirrors substituting for pinholes. The design is ideal for observations of transient luminous phenomena or fast-moving objects, such as upper atmospheric lightning and bright gamma ray bursts. The advantage of the MEMS "obscura telescope" over conventional cameras is that it is capable both of searching for events over a wide field of view, and fast zooming to allow detailed investigation of the structure of events. It is also able to track the triggering object to investigate its space-time development, and to center the interesting portion of the image on the photodetector array. We present the proposed system and the test results for the MEMS obscura telescope which has a field of view of 11.3 degrees, sixteen times zoom-in and tracking within 1 ms. (c) 2008 Optical Society of America

  17. The afterglow of the short/intermediate-duration gamma-ray burst GRB 000301C: A jet at z=2.04

    DEFF Research Database (Denmark)

    Jensen, B.L.; Fynbo, J.U.; Gorosabel, J.

    2001-01-01

    was subsequently discovered with the Nordic Optical Telescope (NOT) about 42 h after the burst. The GRB lies at the border between the long-soft and the short-hard classes of GRBs. If GRB 000301C belongs to the latter class, this would be the first detection of an afterglow to a short-hard burst. We present UBRI...... the burst. The optical light curve is consistent with bring achromatic from 2 to 11 days after the burst and exhibits a break. A broken power-law fit yields a shallow pre-break decay power-law slope of alpha (1) = -0.72 +/- 0.06, a break time of t(break) = 4.39 +/- 0.26 days after the burst, and a post.......0404 +/- 0.0008. We find evidence for a curved shape of the spectral energy distribution of the observed afterglow. It is best fitted with a power-law spectral distribution with index beta similar to -0.7 reddened by an SMC-like extinction law with A(v) similar to 0.1 mag. Based on the Ly alpha absorption...

  18. Simultaneous NuSTAR/Chandra Observations of the Bursting Pulsar GRO J1744-28 During its Third Reactivation

    Science.gov (United States)

    Younes, G.; Kouveliotou, C.; Grefenstette, B. W.; Tomsick, J. A.; Tennant, A.; Finger, M. H.; Furst, F.; Pottschmidt, K.; Bhalerao, V.; Boggs, S. E.; hide

    2015-01-01

    We report on a 10 ks simultaneous Chandra/High Energy Transmission Grating (HETG)-Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the Bursting Pulsar, GRO J1744-28, during its third detected outburst since discovery and after nearly 18 yr of quiescence. The source is detected up to 60 keV with an Eddington persistent flux level. Seven bursts, followed by dips, are seen with Chandra, three of which are also detected with NuSTAR. Timing analysis reveals a slight increase in the persistent emission pulsed fraction with energy (from 10% to 15%) up to 10 keV, above which it remains constant. The 0.5-70 keV spectra of the persistent and dip emission are the same within errors and well described by a blackbody (BB), a power-law (PL) with an exponential rolloff, a 10 keV feature, and a 6.7 keV emission feature, all modified by neutral absorption. Assuming that the BB emission originates in an accretion disk, we estimate its inner (magnetospheric) radius to be about 4 x 10(exp 7) cm, which translates to a surface dipole field B approximately 9 x 10(exp 10) G. The Chandra/HETG spectrum resolves the 6.7 keV feature into (quasi-)neutral and highly ionized Fe XXV and Fe XXVI emission lines. XSTAR modeling shows these lines to also emanate from a truncated accretion disk. The burst spectra, with a peak flux more than an order of magnitude higher than Eddington, are well fit with a PL with an exponential rolloff and a 10 keV feature, with similar fit values compared to the persistent and dip spectra. The burst spectra lack a thermal component and any Fe features. Anisotropic (beamed) burst emission would explain both the lack of the BB and any Fe components.

  19. Emergent synchronous bursting of oxytocin neuronal network.

    Directory of Open Access Journals (Sweden)

    Enrico Rossoni

    2008-07-01

    Full Text Available When young suckle, they are rewarded intermittently with a let-down of milk that results from reflex secretion of the hormone oxytocin; without oxytocin, newly born young will die unless they are fostered. Oxytocin is made by magnocellular hypothalamic neurons, and is secreted from their nerve endings in the pituitary in response to action potentials (spikes that are generated in the cell bodies and which are propagated down their axons to the nerve endings. Normally, oxytocin cells discharge asynchronously at 1-3 spikes/s, but during suckling, every 5 min or so, each discharges a brief, intense burst of spikes that release a pulse of oxytocin into the circulation. This reflex was the first, and is perhaps the best, example of a physiological role for peptide-mediated communication within the brain: it is coordinated by the release of oxytocin from the dendrites of oxytocin cells; it can be facilitated by injection of tiny amounts of oxytocin into the hypothalamus, and it can be blocked by injection of tiny amounts of oxytocin antagonist. Here we show how synchronized bursting can arise in a neuronal network model that incorporates basic observations of the physiology of oxytocin cells. In our model, bursting is an emergent behaviour of a complex system, involving both positive and negative feedbacks, between many sparsely connected cells. The oxytocin cells are regulated by independent afferent inputs, but they interact by local release of oxytocin and endocannabinoids. Oxytocin released from the dendrites of these cells has a positive-feedback effect, while endocannabinoids have an inhibitory effect by suppressing the afferent input to the cells.

  20. Electronic implementation of optical burst switching techniques

    Science.gov (United States)

    Albanese, Ilijc; Darcie, Thomas E.; Ganti, Sudhakar

    2013-10-01

    Extensive research effort is ongoing in energy-efficient Internet-based communications. Optical Flow Switching (OFS) and Optical Burst Switching (OBS) offer potentially efficient alternatives to IP-router-based networks for large data transactions, but significant challenges remain. OFS requires each user to install expensive core network technology, limiting application to highly specialized nodes. OBS can achieve higher scalability but burst assembly/disassembly procedures reduce power efficiency. Finally both OFS and OBS use all-optical switching technologies for which energy efficiency and flexibility remain subject to debate. Our study aims at combining the advantages of both OBS and OFS while avoiding their shortcomings. We consider using a two-way resource reservation protocol for periodic concatenations of large (e.g. 1 Mb) packets or Media Frames (MFs). These chains of MFs (MFCs) are semi-transparent with a periodicity referred to as the "transparency degree". Each MFC is assembled and stored at an end-user machine during the resource reservation procedure and is then switched and buffered electronically along its path. The periodic configuration of each MFC enables interleaving of several chains using buffering only to align the MFs in each MFC in time, largely reducing the buffer requirements with respect to OBS. This periodicity also enables a simple scheduling algorithm to schedule large transactions with minimal control plane processing, achieving link utilization approaching 99.9%. In summary, results indicate that implementing optical burst switching techniques in the electronic domain is a compelling path forward to high-throughput power-efficient networking.